Oil, Gas & Mining Vocabulary: 100 Key English Terms
English is the working language of the oil, gas and mining industries: international operators, drilling contractors, equipment suppliers, lenders and regulators use it in daily reports, safety procedures, contracts and technical manuals. These terms are the words geologists, drillers, engineers, mine supervisors, metallurgists and HSE staff use every day, from exploration and drilling to refining, pipelines, ore processing and site closure.
100 terms
11 topics
47 core terms
200 example sentences
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Exploration & Geology
hydrocarbon
noun
Meaning
A chemical compound made only of hydrogen and carbon. Crude oil and natural gas are mixtures of hydrocarbons, so the word often means oil and gas in general.
Where you use it
Very common in exploration reports, licences and law, where it covers both oil and gas: hydrocarbon exploration, hydrocarbon reserves, a hydrocarbon discovery. Geologists talk about where hydrocarbons are generated, how they migrate and where they are trapped.
Examples
The well found hydrocarbons in two sandstone layers.
The licence gives the company the right to explore for hydrocarbons in the block for six years.
The work of searching for new oil, gas or mineral deposits, using geological mapping, geophysical surveys, sampling and test drilling.
Where you use it
Used for the first, high-risk stage of a project: exploration licence, exploration well, exploration budget, exploration geologist. Companies 'carry out' or 'conduct' exploration and talk about exploration success rates.
Examples
We are planning two exploration wells in the northern block next year.
Exploration around the old copper mine found a new zone of mineralization.
Common phrases
exploration licence · exploration well · exploration drilling · exploration budget · carry out exploration
Rock that contains enough of a valuable metal or mineral to be mined and processed at a profit, for example iron ore or copper ore.
Where you use it
Whether rock counts as ore depends on grade, metal price and cost, so the line between ore and waste can move. Common phrases: iron ore, ore grade, run-of-mine ore, ore body and ore reserves. Ore is mined, hauled, crushed and processed.
Examples
The trucks bring the ore to the primary crusher.
Iron ore prices fell because of lower steel demand.
A method of mapping rock layers underground by sending sound waves into the earth and recording the echoes that bounce back from different layers.
Where you use it
The main tool for finding oil and gas traps before drilling. Surveys are 2D or 3D, onshore (with vibrator trucks or small charges) or marine (with air guns towed behind a ship). Geophysicists acquire, process and interpret the data; people often just say 'the seismic'.
Examples
A 3D seismic survey of the block will be shot next spring.
The seismic survey showed a large structure at about 2,500 metres.
Usage note
'Seismic' starts like 'size': SIZE-mik. Surveys are 'shot', 'run' or 'acquired', not 'made'.
Common phrases
3D seismic survey · shoot a seismic survey · seismic data · seismic interpretation · marine seismic survey
A natural concentration of a mineral, metal, coal, oil or gas in the earth that may be large and rich enough to be worth mining or producing.
Where you use it
Geologists describe deposits by type (porphyry copper deposit, gold deposit), size and grade. A deposit is discovered, defined by drilling, evaluated and developed. In oil and gas, 'accumulation' or 'field' is more usual, but 'oil deposit' appears in general writing.
Examples
The company discovered a large copper deposit about 200 metres below the surface.
New drilling has extended the gold deposit to the east.
Usage note
In everyday English a deposit is also money put into a bank or paid in advance. The stress is on the second syllable: de-PO-sit.
Common phrases
mineral deposit · ore deposit · coal deposit · discover a deposit · develop a deposit
The amount of valuable metal or mineral in a rock, usually given as a percentage (for copper) or in grams per tonne (for gold and silver).
Where you use it
Probably the most important number in mining. People talk about high-grade and low-grade ore, average grade, head grade (ore entering the plant) and cut-off grade (the lowest grade that can be mined at a profit). Grades come from assays of drill samples.
Examples
The best hole returned 25 metres at 4.2 grams per tonne gold, a much higher grade than expected.
Falling grades mean we must process more ore to produce the same amount of copper.
Usage note
Turkish 'tenör' comes from French 'teneur'. In English this meaning is 'grade'; 'tenor' is a singing voice.
Common phrases
high-grade ore · low-grade ore · cut-off grade · head grade · average grade
A long cylinder of rock cut out by a hollow drill bit and brought to the surface so geologists can study and test the rock as it was underground.
Where you use it
Usually called 'core'. In mining, diamond drilling produces core that is logged, photographed, split and sent for assay. In oil and gas, small core plugs are tested in the lab for porosity and permeability. Core is kept in core boxes in a core shed.
Examples
The core samples from this hole show visible gold in quartz veins.
We took a 30-metre core sample through the main reservoir section.
Common phrases
take a core sample · diamond core drilling · core logging · core box · core shed
The share of a rock's volume made up of empty spaces (pores) that can hold oil, gas or water, usually given as a percentage.
Where you use it
Together with permeability, the main measure of reservoir quality. Geologists measure it from cores and well logs and talk about good or poor porosity, for example 'porosity of 18 percent'. Sandstones and some limestones often have good porosity.
Examples
Porosity in the main sandstone averages 22 percent.
The rock had good porosity but very low permeability, so the oil could not flow.
Common phrases
high porosity · average porosity · porosity log · effective porosity
How easily fluids can flow through a rock, which depends on how well its pores are connected. It is measured in darcies or millidarcies (mD).
Where you use it
A rock can hold a lot of oil (high porosity) but still produce little if its permeability is low. Tight reservoirs and shale have very low permeability and often need hydraulic fracturing. Engineers often say 'perm' for short.
Examples
Permeability in this zone is only about 0.1 millidarcy.
Low permeability explains why the well's flow rate is so poor.
A well that does not find oil or gas in amounts worth producing. It is usually plugged and abandoned.
Where you use it
Also called a duster. Dry holes are a normal part of exploration risk, and companies report the dry hole costs they write off. Press releases often use softer wording such as 'did not encounter commercial hydrocarbons'.
Examples
The second exploration well was a dry hole and has been plugged.
Two dry holes in a row made the partners rethink their plans for the block.
Usage note
A dry hole may still contain water; it is called 'dry' because it has no commercial oil or gas.
Common phrases
drill a dry hole · dry hole cost · plug a dry hole · dry hole risk
To find oil by drilling. In everyday English it also means to suddenly find something that brings great success or a lot of money.
Where you use it
More common in news, history and storytelling than in technical reports, which prefer 'make a discovery' or 'encounter hydrocarbons'. The past forms are 'struck oil' and 'have struck oil'. The same idea appears in 'strike gold' and 'a lucky strike'.
Examples
The company hopes to strike oil before its licence expires.
Edwin Drake's success in striking oil in Pennsylvania in 1859 is seen as the start of the modern US oil industry.
Usage note
The past form is 'struck', not 'striked'.
Common phrases
strike oil · strike gas · strike it rich · strike gold
A continuous mass of ore in the ground with a known shape, size and grade that can be mined as a unit.
Where you use it
Also written orebody. Geologists model the ore body in 3D from drill holes and talk about its strike, dip, width and depth. Mine planners choose a mining method that fits the shape of the ore body.
Examples
The ore body is about 30 metres wide and dips steeply to the north.
Drilling showed that the ore body continues below 600 metres.
Common phrases
ore body model · define the ore body · massive ore body · ore body geometry
A laboratory test that measures how much gold, copper or another metal a rock, soil or concentrate sample contains.
Where you use it
Also a verb: to assay a sample. Exploration companies wait for assay results and announce them to investors. Common methods are fire assay for gold and acid digestion with ICP analysis for many other metals. Quality control uses blanks, duplicates and standards.
Examples
Assay results from the last ten drill holes are expected next week.
Each metre of core is split, and one half is sent to the lab for assay.
Usage note
Do not confuse it with 'essay' (a piece of writing). The noun is often stressed on the first syllable (AS-say) and the verb on the second (as-SAY).
Common phrases
assay results · fire assay · assay lab · assay a sample · pending assays
A deep, narrow hole drilled into the ground to find or produce oil, gas or water, or to inject fluids back into a reservoir.
Where you use it
Wells are drilled, completed, tested, put on production, shut in and finally plugged and abandoned. Types include exploration, appraisal, production and injection wells. Engineers refer to each well by its name and number, for example 'Well K-12'.
Examples
The well reached a total depth of 3,450 metres on Tuesday.
We have to shut in the well before the workover crew arrives.
Usage note
Turkish uses 'kuyu' for both an oil well and a mine shaft; in English these are different words: 'well' for drilling, 'shaft' for mining.
Common phrases
drill a well · exploration well · production well · injection well · plug and abandon a well
The complete set of machinery used to drill a well, including the tower, engines, pumps, hoisting system and the equipment that turns the drill pipe.
Where you use it
Usually shortened to 'rig'. People talk about land rigs and offshore rigs (jack-ups, semi-submersibles, drillships), rig count, rig time and day rate. Crews 'rig up' when they set up and 'rig down' when they dismantle before a rig move.
Examples
The drilling rig will move to the next location once this well is finished.
The day rate for the offshore drilling rig is the biggest cost in the well budget.
Usage note
The derrick is only the tall tower; the rig is the whole system. In Turkish both are often called 'kule'.
Common phrases
land drilling rig · offshore drilling rig · rig up · rig move · rig count
The cutting tool at the bottom of the drill string that breaks and crushes rock as it turns, making the hole deeper.
Where you use it
Usually just 'the bit'. Drillers discuss bit type (roller cone or PDC), bit size in inches, bit wear and rate of penetration (ROP). When a bit is worn out, the crew pulls the string out of the hole to change it.
Examples
The drill bit was badly worn when we pulled it out at 2,100 metres.
Switching to a PDC drill bit doubled our rate of penetration in the shale.
Common phrases
change the drill bit · PDC bit · roller cone bit · bit wear · rate of penetration (ROP)
A specially mixed fluid pumped down the drill pipe and back up the hole to cool the bit, carry rock cuttings to the surface and control well pressure.
Where you use it
Called 'mud' on the rig and 'drilling fluid' in technical writing. The mud engineer checks mud weight, viscosity and losses. Water-based and oil-based mud are the main types. Heavier mud is used to hold back high formation pressure.
Examples
We raised the weight of the drilling mud after the gas readings increased.
Cuttings carried up by the drilling mud are checked by the geologist every ten metres.
Large steel pipe lowered into a newly drilled section of a well and cemented in place to stop the hole collapsing and to keep rock layers and fluids apart.
Where you use it
Wells are built in steps: drill a section, run casing, cement it, then drill deeper with a smaller bit. Each casing string has a size in inches (13 3/8-inch, 9 5/8-inch). Common phrases are run casing, casing shoe, casing string and casing pressure.
Examples
We will run the 9 5/8-inch casing tomorrow and cement it on Thursday.
A leak in the casing allowed water into the well.
Common phrases
run casing · casing string · casing shoe · cement the casing · production casing
An uncontrolled release of oil, gas or water from a well after the pressure control systems fail. It can cause fires, deaths and serious pollution.
Where you use it
The worst event in well operations, so well control training is built around preventing it. A kick that is not controlled can turn into a blowout. People talk about a well blowout, blowout risk and blowout prevention.
Examples
The Deepwater Horizon blowout in the Gulf of Mexico in 2010 killed eleven workers.
Good kick detection is our first line of defence against a blowout.
Usage note
The noun is one word (a blowout); the phrasal verb is two words (the well blew out).
Common phrases
well blowout · blowout preventer (BOP) · prevent a blowout · blowout risk
A large stack of heavy valves fitted on top of a well that can be closed quickly to seal the well and stop oil or gas escaping during drilling.
Where you use it
Almost always called 'the BOP' (B-O-P). A BOP stack contains annular preventers and ram preventers (pipe rams, blind rams, shear rams). It is regularly pressure-tested and function-tested, and closing it is the first step when a kick is detected.
Examples
The blowout preventer was pressure-tested before we drilled out of the casing shoe.
The driller closed the blowout preventer as soon as he saw the pit gain.
Common phrases
BOP stack · close the BOP · BOP test · shear rams · subsea BOP
The work done after drilling to make a well ready to produce safely, such as running production tubing, perforating the casing and installing valves.
Where you use it
Usually just 'completion'; the verb is 'complete a well'. Completion engineers design it, and well costs are often reported as drilling and completion (D&C). Completion types include open hole and cased hole completions.
Examples
The well completion is finished, and the well will be put on production next week.
The well completion design includes sand screens because the reservoir rock is weak.
Common phrases
complete a well · completion engineer · completion design · drilling and completion (D&C)
To start drilling a new well, from the moment the bit first enters the ground or the seabed.
Where you use it
Used in drilling reports, press releases and contracts: 'the well was spudded on 3 May'. The spud date marks the start of a well, and drilling time is measured from spud to total depth (TD). The noun 'spud-in' is also used.
Examples
We expect to spud the well next Monday.
The well was spudded on 12 March and reached TD in 41 days.
Usage note
The past form doubles the 'd': spudded.
Common phrases
spud a well · spud date · spud-in · from spud to TD
To pull the drill string out of the well or run it back in, for example to change a worn bit or a tool. The whole operation is called a trip.
Where you use it
Rig crews say trip out (POOH, pull out of hole) and trip in (RIH, run in hole). Tripping takes many hours on deep wells and is a risky time for well control, so the trip tank is watched closely. A round trip means out and back in again.
Examples
We tripped out to change the bit at 2,800 metres.
While tripping out, the driller noticed that the hole was taking less mud than expected.
Usage note
'Trip' also means a short journey, and in plant English a machine that 'trips' shuts down automatically. On a rig, it is about moving the drill string.
Common phrases
trip out of the hole · trip in · round trip · trip tank · tripping time
An unwanted flow of gas, oil or water from the rock into the well, which happens when the formation pressure is higher than the pressure of the mud column.
Where you use it
A key well control word. Warning signs include a pit gain (mud tanks filling up), increased flow and a drilling break. The crew must detect the kick, shut in the well with the BOP and 'kill the well' by pumping heavier mud. An uncontrolled kick can become a blowout.
Examples
We took a kick at 3,100 metres and shut in the well immediately.
A 10-barrel pit gain is a clear sign of a kick.
Usage note
Drillers say they 'took a kick'; it has nothing to do with kicking someone.
Common phrases
take a kick · detect a kick · kick detection · circulate out a kick · kill the well
The long column of connected drill pipe, heavy collars and tools that runs from the rig down to the bit, turning it and carrying drilling mud to the bottom of the hole.
Where you use it
Rig crews say 'the string' for short. The lower part with the bit, drill collars and tools is the bottom hole assembly (BHA). Common problems are stuck pipe and twist-offs. The string is tripped in and out of the hole one stand at a time.
Examples
The drill string got stuck at 2,650 metres after a shale section collapsed.
We pulled the drill string to change the bottom hole assembly.
Oil in its natural state as it comes out of the ground, before it is refined into fuels such as gasoline, diesel and jet fuel.
Where you use it
Often shortened to 'crude' in trading, shipping and news: crude prices, crude exports, a crude tanker. Crudes are described by density (light or heavy) and sulphur content (sweet or sour). Production is measured in barrels per day.
Examples
The field produces about 20,000 barrels of crude oil per day.
Crude oil prices rose after the producers announced a cut in output.
Usage note
False friend: in British English 'petrol' is the fuel you put in a car (US 'gasoline'), not crude oil. Turkish 'petrol' is 'oil' or 'crude oil' in English.
Common phrases
crude oil price · light crude oil · heavy crude oil · crude oil production · crude oil tanker
A gas fuel found underground, made mostly of methane and often found with oil. It is used for heating, cooking, power plants and as a raw material for industry.
Where you use it
In the industry often just 'gas'. Volumes are given in cubic metres (bcm, billion cubic metres) or cubic feet (Mcf, MMscf, Tcf). Gas found together with oil is called associated gas. Gas is sent by pipeline or cooled into LNG and shipped.
Examples
The new offshore field will deliver natural gas to the onshore processing plant by pipeline.
Demand for natural gas peaks in winter, when households turn on their heating.
Usage note
In American English 'gas' also means gasoline (car fuel), so 'gas prices' in US news usually means pump prices for gasoline.
Common phrases
natural gas field · natural gas reserves · associated gas · natural gas supply
A layer of porous rock deep underground that holds oil or gas in the tiny spaces between its grains, with rock above it that stops the fluids escaping.
Where you use it
Central to geology and production work: reservoir engineers model how fluids move and how much can be produced. Common phrases are reservoir pressure, reservoir rock, reservoir quality and reservoir simulation.
Examples
Reservoir pressure has dropped by 15 percent since production started.
The limestone reservoir is about 40 metres thick and has good porosity.
Usage note
Oil is not stored in an underground lake or cave; it fills the small pores inside solid rock, like water in a sponge.
Located or happening at sea, away from the coast, for example an oil field, platform or rig in the sea. The opposite is onshore.
Where you use it
Used as an adjective (offshore field, offshore rig, offshore worker) and as an adverb (he works offshore). Offshore staff usually work rotations such as two weeks on, two weeks off and travel by helicopter. Deep water and ultra-deep water describe the deepest projects.
Examples
The Sakarya gas field is an offshore discovery in the Black Sea.
She works offshore on a three-week rotation.
Usage note
In finance, 'offshore' also means based in another country for tax reasons (an offshore account). The context tells you which meaning is intended.
Common phrases
offshore field · offshore platform · offshore rig · work offshore · offshore and onshore
The steel equipment at the top of a well, at the surface or on the seabed, that holds the casing and tubing and connects the well to valves and flowlines.
Where you use it
On a producing well, a set of valves called the Christmas tree sits on the wellhead. Operators read wellhead pressure and temperature. The word also appears in pricing: the wellhead price is the value of oil or gas before transport.
Examples
Wellhead pressure dropped to 850 psi overnight.
The subsea wellhead sits on the seabed at a water depth of 1,200 metres.
Usage note
A 'Christmas tree' (or just 'tree') is the valve assembly on the wellhead; it has nothing to do with the holiday except its shape.
Pumping water, sand and chemicals into a well at very high pressure to crack the rock, so oil or gas can flow more easily from tight formations such as shale.
Where you use it
Called fracking in the news and 'frac' in the industry (a frac job, frac fleet, frac sand). Combined with horizontal drilling, it made the US shale boom possible. It is debated because of water use, induced earthquakes and possible groundwater contamination.
Examples
Each horizontal well is completed with 40 stages of hydraulic fracturing.
Some countries have banned hydraulic fracturing over environmental concerns.
Usage note
Engineers usually spell the short form 'frac'; 'fracking' is the spelling used in the media.
Methods used to get more oil out of a mature field than natural pressure and water injection can, for example by injecting CO2, steam or chemicals into the reservoir.
Where you use it
Also called tertiary recovery. Engineers compare primary recovery (natural flow), secondary recovery (water or gas injection) and EOR. Common types are CO2 flooding, steam injection for heavy oil and polymer flooding. Projects are judged by the extra barrels they add.
Examples
An enhanced oil recovery project using CO2 could add 30 million barrels from the field.
Steam injection is the most common enhanced oil recovery method for heavy oil.
A pressure vessel at a production facility that splits the mixed flow from the wells into oil, gas and water so that each can be treated and sent on separately.
Where you use it
Separators can be two-phase (gas and liquid) or three-phase (oil, gas and water), horizontal or vertical. Operators watch separator pressure and liquid levels; a test separator measures the flow from one well at a time.
Examples
Well K-7 is flowing through the test separator today.
A high water level in the separator caused a shutdown last night.
Common phrases
test separator · three-phase separator · separator pressure · production separator
The amount of oil, gas or water that flows from a well or through a pipe in a given time, such as barrels per day or cubic metres per hour.
Where you use it
Reported daily in production reports and well tests: 'the well tested at a flow rate of 3,000 bopd'. Engineers talk about initial flow rates, decline, the choke size that controls the rate, and the maximum flow rate of a pipeline.
Examples
The flow rate dropped after we reduced the choke size.
During the test, the well reached a flow rate of 18 million cubic feet of gas per day.
Common phrases
initial flow rate · measure the flow rate · maximum flow rate · stable flow rate
To close the valves on a well so that it stops flowing, for safety, repairs or a test, or because the production is not needed.
Where you use it
Used as a verb (shut in the well, the well was shut in) and as an adjective (a shut-in well, shut-in pressure). During drilling, the crew shuts in the well when a kick is detected. Production reports list shut-in wells and the reasons.
Examples
We shut in three wells because the export pipeline is down.
Shut-in pressure at the wellhead was 2,400 psi.
Usage note
Written as two words for the verb (shut in the well) and with a hyphen as an adjective (a shut-in well).
Common phrases
shut in a well · shut-in pressure · shut-in well · shut in production
Short for floating production, storage and offloading unit: a ship-shaped vessel moored over an offshore field that processes oil from subsea wells, stores it and transfers it to tankers.
Where you use it
Said as letters (F-P-S-O). Common in deep-water and remote fields without pipelines, for example off Brazil and West Africa. Many are converted from old oil tankers. Words used with it include topsides, turret mooring, risers and offloading.
Examples
The FPSO can store up to 1.6 million barrels of oil.
A shuttle tanker loads crude from the FPSO about every ten days.
A large structure standing on the seabed or floating at sea that holds the equipment and living quarters needed to drill wells or produce oil and gas offshore.
Where you use it
Types include fixed platforms on steel jackets, jack-ups, semi-submersibles and tension-leg platforms. People talk about the topsides, helideck and accommodation module, and they fly 'out to the platform' by helicopter. 'Rig' is used more for drilling units, 'platform' more for production.
Examples
The gas platform sends its production to shore through a 60-kilometre pipeline.
Bad weather delayed the crew change flight to the platform.
An industrial plant where crude oil is heated, separated and chemically changed to make products such as gasoline, diesel, jet fuel, LPG and asphalt.
Where you use it
Refineries are described by their capacity in barrels per day and by their complexity. Staff talk about refinery units, turnarounds (planned maintenance shutdowns), throughput and refining margins. A refinery 'processes' or 'runs' crude.
Examples
The refinery processes about 200,000 barrels of crude a day.
Two units at the refinery will be shut down for a six-week turnaround.
The first main step in refining: crude oil is heated, and its vapours rise in a tall column and condense at different heights into fractions such as gasoline, kerosene and diesel.
Where you use it
Refinery staff talk about the crude distillation unit (CDU), atmospheric distillation and vacuum distillation. The products are called fractions or cuts, and the heavy part left at the bottom is the residue.
Examples
The crude distillation unit is the heart of the refinery.
Heavy residue from atmospheric distillation goes to the vacuum unit.
Common phrases
crude distillation unit (CDU) · atmospheric distillation · vacuum distillation · distillation column
A refining process that breaks large, heavy hydrocarbon molecules into smaller, lighter ones, turning low-value heavy oil into more gasoline, diesel and other products.
Where you use it
Types include fluid catalytic cracking (FCC), hydrocracking and thermal cracking; steam cracking is used to make ethylene. Refinery staff talk about the FCC unit, the cracker and conversion. Refineries with more cracking capacity are called complex refineries.
Examples
The new hydrocracking unit lets us turn heavy residue into diesel.
Catalytic cracking produces a large share of the refinery's gasoline.
The raw material fed into a refinery unit or chemical plant to be processed, for example crude oil for a refinery or naphtha for a petrochemical plant.
Where you use it
Used in refining, petrochemicals and gas processing: feedstock quality, feedstock costs, alternative feedstocks. A change in feedstock changes the product yields, so planners choose the crude mix carefully.
Examples
Naphtha is the main feedstock for the steam cracker.
Feedstock costs make up most of the plant's operating expenses.
A chemical made from oil or natural gas, such as ethylene, propylene or benzene, used to make plastics, fibres, fertilisers and many other products.
Where you use it
Usually plural as a noun (petrochemicals) and very common as an adjective: petrochemical plant, petrochemical complex, petrochemical industry. Many refineries are integrated with petrochemical units, so part of their output goes to chemicals instead of fuels.
Examples
Aliağa, near İzmir, is home to Turkey's main petrochemical complex.
Demand for petrochemicals is growing faster than demand for transport fuels.
A scale created by the American Petroleum Institute that shows how light or heavy a crude oil is compared with water. A higher number means lighter oil; water is 10 degrees.
Where you use it
Given in degrees: a 35° API crude. Light crudes (roughly above 31°) usually yield more gasoline and diesel and sell at higher prices; heavy crudes (below about 22°) need more processing. Traders quote API gravity and sulphur content together.
Examples
The crude has an API gravity of 38 degrees and very little sulphur.
Oil with a low API gravity flows slowly and may need heating or diluting for transport.
Usage note
The scale works the opposite way to density: the denser the oil, the lower its API gravity.
Common phrases
degrees API · light crude · heavy crude · crude assay
Crude oil with a high sulphur content, usually more than 0.5 percent. Crude with little sulphur is called sweet crude.
Where you use it
Sour crude is cheaper because refineries need extra units to remove the sulphur, and it may contain H2S that is dangerous to handle. Traders and refiners talk about light sweet, medium sour and heavy sour grades. The same words describe gas: sour gas and sweet gas.
Examples
The refinery was upgraded so that it can process cheaper sour crude.
Sour crude from this field needs H2S monitoring at the loading terminal.
Usage note
Here 'sour' and 'sweet' are about sulphur, not taste. Early oilmen are said to have judged crude by its smell and taste.
Common phrases
sweet crude · light sweet crude · medium sour crude · sour gas
A long line of connected pipes, often buried or laid on the seabed, used to carry oil, gas, water or slurry over long distances.
Where you use it
Pipelines are designed, laid, tested, commissioned and operated. Engineers talk about diameter in inches, operating pressure, capacity and right of way (the strip of land the line uses). Pipeline operators monitor flow and pressure from a control centre.
Examples
The pipeline carries gas from the coast to a compressor station 300 kilometres inland.
A leak was detected on the crude oil pipeline near the river crossing.
Usage note
The idiom 'in the pipeline' means 'being planned or prepared', for example 'two new projects are in the pipeline'.
Common phrases
gas pipeline · oil pipeline · lay a pipeline · pipeline capacity · pipeline route
Short for liquefied natural gas: natural gas cooled to about minus 162°C so it becomes a liquid that takes up around 600 times less space and can be shipped by tanker.
Where you use it
Said as letters (L-N-G). The chain includes liquefaction plants, LNG carriers, import terminals and regasification, often on an FSRU (floating storage and regasification unit). Traders talk about LNG cargoes, spot LNG and long-term LNG contracts.
Examples
Turkey imports LNG through terminals and FSRUs on its coasts.
An LNG carrier arrived at the terminal and began unloading.
Usage note
Do not confuse LNG with LPG (liquefied petroleum gas, mainly propane and butane), which is used in cars and gas cylinders.
A large container, usually a round steel tank, used to hold crude oil, fuels, water or chemicals at a terminal, refinery or production site.
Where you use it
A tank farm holds many storage tanks; floating-roof tanks are used for crude and gasoline to reduce vapour losses. Operators talk about tank capacity, tank level, gauging and bunds (walls around tanks that hold spills).
Examples
The terminal has twelve storage tanks with a total capacity of one million barrels.
Water was drained from the bottom of the crude storage tank.
Common phrases
tank farm · floating-roof tank · tank capacity · tank level · tank gauging
A facility along a gas pipeline that uses compressors to raise the pressure of the gas so that it keeps flowing over long distances.
Where you use it
Gas loses pressure as it travels, so stations are built at intervals along the line, often 100 kilometres or more apart. Operators talk about compressor units, gas turbines, discharge pressure and station capacity. Stations are often controlled remotely.
Examples
A new compressor station will raise the pipeline's capacity by 20 percent.
One unit at the compressor station tripped, and gas flow dropped.
Usage note
In plant English, a unit that 'trips' shuts down automatically, usually because a safety limit was reached.
Common phrases
gas compressor · compressor unit · discharge pressure · station capacity
A device pushed through a pipeline by the flow to clean it, separate products or inspect the pipe wall from inside. Smart pigs carry sensors that find corrosion and cracks.
Where you use it
Also a verb: to pig a line; the operation is called pigging. Pigs are put in at a pig launcher and taken out at a pig receiver. In-line inspection (ILI) tools are called smart or intelligent pigs.
Examples
We run a cleaning pig through the line every month.
The smart pig found several areas of corrosion near the river crossing.
Usage note
The name is often said to come from the squealing noise early pigs made inside the pipe, but nobody knows for sure.
Common phrases
pig launcher · pig receiver · smart pig · pigging operation · run a pig
The amount of material that passes through a pipeline, plant or terminal in a given period, such as barrels per day or tonnes per hour.
Where you use it
Used for pipelines (pipeline throughput), refineries (crude throughput) and processing plants (mill throughput). Managers set throughput targets and look for bottlenecks. Throughput is the actual amount; capacity is the maximum possible.
Examples
Mill throughput reached a record 1,500 tonnes per hour in May.
Pipeline throughput fell when two fields went offline for maintenance.
A place where coal, metal ores or other minerals are dug out of the ground, either from a large surface pit or through tunnels underground.
Where you use it
Also a verb: to mine copper, mined ore. People talk about a gold mine, coal mine, mine site, mine life (how many years it can operate) and mine plan. Miners work at the face; the mine manager runs the whole operation.
Examples
The mine produces about 3 million tonnes of ore a year.
Copper has been mined in this valley since ancient times.
Usage note
Do not confuse it with the pronoun 'mine' (benim). 'A gold mine' is also an idiom for something that makes a lot of money.
Common phrases
coal mine · gold mine · mine site · mine life · mine plan
A mine where ore is dug from the surface in a large, stepped hole that gets wider and deeper over time, instead of through underground tunnels.
Where you use it
Also called an opencast mine (mainly British, especially for coal) or a surface mine. Typical words are pit, bench, haul road, pit wall, stripping and drill and blast. Engineers 'design the pit' and talk about pit depth and pit expansion.
Examples
The open-pit mine is now 400 metres deep.
When the open-pit mine reaches its final depth, the company plans to go underground.
A mine where ore or coal is reached through shafts, declines or tunnels and extracted below the surface, used when the deposit is too deep for an open pit.
Where you use it
Underground work has its own vocabulary: shaft, decline (a sloping tunnel), level, drift, stope, face, ventilation and roof support. People say they work 'underground' or 'below ground' and discuss mining methods such as room and pillar or longwall.
Examples
The underground mine has five working levels connected by a decline.
Most of the coal in this region comes from underground mines.
Breaking rock with explosives placed in drilled holes so it can be loaded and removed. It is a daily task in open pits, underground mines and quarries.
Where you use it
Part of the drill and blast cycle. A shotfirer or blaster designs and fires the blast; the area is cleared before blasting and checked after it. Common terms: blast pattern, blast hole, charge, misfire, fly rock and blast vibration.
Examples
Blasting is scheduled for 1:30 p.m., so all personnel must leave the pit by 1:15.
Nearby villagers complained about vibration from the blasting.
Usage note
Blasting is a planned, controlled job; the word 'explosion' usually describes an accident.
A vertical or steeply sloping tunnel sunk from the surface into an underground mine, used to move workers, ore, materials and air.
Where you use it
Shafts are 'sunk', and the work is called shaft sinking. A headframe stands above the shaft, and a hoist (winder) moves the cage, which carries people, and the skip, which carries ore. Mines may have production shafts and ventilation shafts.
Examples
The new shaft will reach a depth of 1,100 metres.
At the start of the shift, the crew goes down the shaft in the cage.
Usage note
Turkish 'kuyu' covers both an oil well and a mine shaft. In English, use 'well' for drilling and 'shaft' for mines; an 'oil shaft' is wrong.
Common phrases
sink a shaft · shaft sinking · ventilation shaft · production shaft · shaft headframe
The soil and waste rock lying on top of an ore body or coal seam, which must be removed before the valuable material can be mined.
Where you use it
Common in open-pit and coal mining. Removing it is called stripping. Mine planners talk about overburden thickness, overburden removal and where to dump it. Topsoil is usually stored separately so it can be used later for rehabilitation.
Examples
We moved 4 million cubic metres of overburden last year.
The overburden is thin in the south, so mining will start there.
The system that moves fresh air through an underground mine to supply oxygen, remove dust, heat and dangerous gases, and keep the air safe to breathe.
Where you use it
Mines use main fans on the surface, ventilation shafts, auxiliary fans and ducting. Ventilation officers measure airflow and gas levels. Common phrases are intake air, return air and ventilation plan. Losing ventilation in a coal mine is an emergency.
Examples
Work stopped at the face until ventilation was restored.
The new ventilation shaft will double the airflow to the lower levels.
Common phrases
mine ventilation · ventilation shaft · main fan · auxiliary ventilation · ventilation survey
A long steel rod fixed into a hole drilled in the roof or walls of an underground tunnel to hold loose rock layers together and stop them falling.
Where you use it
Also called a rock bolt. Roof bolts are installed by a roof bolter (a drilling machine) as part of ground support, often with steel mesh and shotcrete. Inspectors check bolt spacing and length. Working under unsupported roof is forbidden in most mines.
Examples
Install roof bolts on a 1.5-metre pattern before the next cut.
A slab of rock fell between the roof bolts, but nobody was injured.
Common phrases
install roof bolts · roof bolter · rock bolt · ground support · bolting pattern
An underground coal mining method in which a shearer cuts coal along a long face under moving hydraulic roof supports; behind the supports, the roof is allowed to collapse.
Where you use it
The main high-output method for underground coal. Key words are longwall face, shearer, armoured face conveyor (AFC), shields and goaf (or gob), the collapsed area behind the face. Room and pillar mining is the main alternative.
Examples
Longwall mining recovers more of the seam than room and pillar mining.
The mine switched to longwall mining after the new shearer was delivered.
Common phrases
longwall face · longwall shearer · longwall move · hydraulic shields · room and pillar
A layer of coal or another mineral lying between layers of other rock. It may be a few centimetres or many metres thick.
Where you use it
Mainly used for coal: coal seam, seam thickness, seam gas. Miners describe a seam by its thickness, dip and depth, and whether it is gassy. Seams are named or numbered, for example 'the lower seam'.
Examples
The main coal seam is 3.2 metres thick at this depth.
This seam is very gassy, so methane drainage is needed before mining.
Usage note
In everyday English a seam is the line where two pieces of cloth are sewn together.
Common phrases
coal seam · seam thickness · thin seam · seam gas · work a seam
In an open-pit mine, the amount of waste rock that must be removed for each unit of ore mined; a ratio of 4:1 means four tonnes of waste for every tonne of ore.
Where you use it
Also called strip ratio. It is a key cost driver: a higher stripping ratio means more trucks, fuel and time. Planners weigh the stripping ratio against grade to decide how deep a pit can go before moving underground makes more sense.
Examples
The stripping ratio will rise to 6:1 in the final years of the pit.
Coal mines with a low stripping ratio have much lower costs.
Usage note
Units vary: metal mines usually give tonnes of waste per tonne of ore, while coal mines often use bank cubic metres per tonne.
Common phrases
strip ratio · waste-to-ore ratio · high stripping ratio · life-of-mine stripping ratio
One of the flat, step-like levels cut into the walls of an open pit or quarry, where drilling, blasting and loading take place.
Where you use it
Each bench has a bench height (often 10 to 15 metres in large pits), a face, a crest and a toe. Mining moves down bench by bench, and safety berms catch falling rock. Benches are often named by elevation: 'we are mining the 640 bench'.
Examples
The bench height in the main pit is 12 metres.
Drilling on the 580 bench will finish tomorrow, and we blast on Friday.
Usage note
In everyday English a bench is a long seat; in mining it is a step in the pit wall.
A machine that breaks large rocks into smaller pieces. Crushing is the first step in ore processing, before grinding.
Where you use it
Plants have primary, secondary and tertiary crushers. Common types are jaw, gyratory, cone and impact crushers. Operators talk about crusher throughput, feed size, blockages and liners. Trucks 'tip' or 'dump' ore into the primary crusher.
Examples
The primary crusher was down for two hours because a large rock got stuck.
Ore leaves the crusher at less than 150 millimetres and goes to the mill.
The main product of a processing plant: a powder in which the valuable mineral is much richer than in the original ore, ready to be sold or sent to a smelter.
Where you use it
Used for copper, zinc, lead and other base metals: copper concentrate, concentrate grade, concentrate sales. Sales contracts mention moisture content and penalty elements such as arsenic. As a verb, to concentrate ore means to make the valuable part richer.
Examples
The plant produces a copper concentrate grading 25 percent copper.
Concentrate is trucked to the port and shipped to smelters in Asia.
Usage note
In everyday English 'concentrate' is mostly a verb meaning 'focus your attention'; in mineral processing it is usually a noun for the product.
A process that separates valuable minerals from waste: chemicals make the mineral particles stick to air bubbles, which rise to form a froth that is skimmed off.
Where you use it
The main method for copper, lead, zinc and many other sulphide ores. Plant staff talk about flotation cells, reagents (collectors, frothers), rougher and cleaner stages and flotation recovery. Metallurgists adjust air, pH and reagent dosage to improve results.
Examples
Flotation recovery improved after we changed the collector.
The ground ore is mixed with reagents before it enters the flotation cells.
Usage note
The standard spelling is 'flotation', although the verb is 'float'. You may still see the older spelling 'floatation'.
The stage after crushing in which ore is ground into a fine powder in rotating mills so that the valuable mineral grains are freed from the waste rock.
Where you use it
Often the most energy-hungry step in a plant. Common mills are SAG (semi-autogenous grinding) mills and ball mills; operators talk about grind size, mill throughput, mill liners and grinding media (steel balls). The verb is 'grind' (ground, ground).
Examples
Finer grinding improved gold recovery by 3 percent.
The grinding circuit uses one SAG mill and two ball mills.
Common phrases
grinding circuit · grinding mill · grinding media · SAG mill · ball mill
Dissolving a metal out of ore with a chemical solution, for example cyanide for gold or sulphuric acid for copper, and then recovering the metal from the solution.
Where you use it
In heap leaching, crushed ore is piled on lined pads and sprayed with solution; in tank leaching it is mixed in tanks. Staff talk about leach pads, pregnant solution (rich in metal), leach recovery and cyanide management.
Examples
Heap leaching is used for low-grade gold ore that would cost too much to mill.
Leaching tests showed 85 percent copper recovery after 90 days.
Heating ore or concentrate to a very high temperature in a furnace to separate the metal from other elements, leaving a waste called slag.
Where you use it
Done at a smelter, which buys concentrate from mines and charges treatment and refining charges (TC/RCs). Smelting is used for copper, lead, zinc, nickel and iron. Words that go with it: furnace, slag, matte, sulphur dioxide and acid plant.
Examples
The concentrate is sent abroad for smelting.
Copper smelting releases sulphur dioxide, which the plant turns into sulphuric acid.
The percentage of the valuable metal in the ore that a processing plant actually manages to capture in its final product.
Where you use it
A key performance figure for metallurgists: a gold recovery of 92 percent means 8 percent is lost, mostly to tailings. Recovery and concentrate grade are reported together, and improving one often lowers the other. In oil and gas, 'recovery factor' is the share of the oil in place that can be produced.
Examples
Copper recovery was 88 percent this month, slightly below plan.
We tested a new reagent to improve the recovery of fine particles.
Usage note
In everyday English, recovery means getting better after an illness or a crisis; in processing it is a percentage.
A large digging machine with a boom, arm and bucket on a rotating cab, used in mines to dig rock and load it into trucks.
Where you use it
Large mining excavators are hydraulic machines or electric rope shovels; operators talk about bucket size, cycle time and loading trucks. A backhoe excavator digs toward the cab, while a face shovel digs away from it. Together these machines are called loading units.
Examples
The excavator loads a 220-tonne truck in four passes.
One of the excavators is down for a hydraulic repair, so production will be lower today.
Usage note
Turkish 'kepçe' is used for several machines; in English a wheel loader, a backhoe loader and an excavator are different machines.
A very large dump truck used in open-pit mines to carry ore and waste rock from the loading area to the crusher, a stockpile or the waste dump.
Where you use it
Sized by payload in tonnes, from about 90 to over 300 tonnes. Mine staff talk about the truck fleet, haul roads, cycle time, payload and dispatch systems. Many large mines now run autonomous haul trucks.
Examples
Each haul truck makes about 25 trips a shift between the pit and the crusher.
A haul truck driver cannot see a small vehicle close to the front wheels, so keep your distance.
A machine with a moving rubber belt on rollers that carries ore, coal or rock continuously from one place to another, for example from a crusher to a stockpile.
Where you use it
Also called a conveyor belt or belt conveyor. Staff talk about belt speed, belt tracking, idlers (rollers), transfer points and spillage. Conveyors are a major cause of injuries, so guards, pull-wire emergency stops and lockout/tagout are essential.
Examples
The overland conveyor carries 4,000 tonnes of ore an hour to the plant.
Never clean up spillage under a running conveyor.
Common phrases
conveyor belt · belt conveyor · overland conveyor · conveyor guard · pull-wire
The tall steel tower on a drilling rig that holds the hoisting equipment used to raise and lower the drill string and casing.
Where you use it
Many modern land rigs have a mast, raised in one piece, rather than a classic derrick, but people use the words loosely. The derrickman works high up on the monkey board, handling pipe during trips. Old photos of oil fields show forests of wooden derricks.
Examples
The derrickman clipped on his harness before climbing the derrick.
A derrick about 45 metres tall stands over the well.
Usage note
In ports and on building sites a 'derrick' is also a type of crane.
Short for personal protective equipment: the hard hat, safety glasses, gloves, boots, high-visibility clothing and other gear workers wear to protect themselves on site.
Where you use it
Said as letters (P-P-E). Site rules state the minimum PPE for each area, and special jobs need extra items such as a harness, respirator or fire-resistant coveralls (FRC). Signs say 'PPE is mandatory beyond this point'.
Examples
Full PPE is required on the drill floor, including gloves and safety glasses.
He was sent off site for not wearing the correct PPE.
Usage note
PPE is uncountable: say 'wear PPE' or 'a piece of PPE', not 'a PPE' or 'PPEs'.
Common phrases
wear PPE · minimum PPE · PPE requirements · PPE check
A written approval that must be issued before high-risk work such as hot work, work at height or work on live equipment, listing the hazards and the agreed controls.
Where you use it
Often shortened to PTW or simply 'permit'. A permit is requested, issued, signed, displayed at the work site and closed out when the job ends. Types include hot work permits, cold work permits and confined space entry permits.
Examples
Nobody starts welding on the platform without a valid permit to work.
The permit to work was closed after the area was checked and cleaned.
Usage note
The plural is 'permits to work'.
Common phrases
issue a permit to work · permit to work system · hot work permit · close out a permit
The chemical formula of hydrogen sulphide, a colourless, highly toxic gas found in some wells and mines. It smells of rotten eggs at low levels but can quickly deaden the sense of smell.
Where you use it
Read aloud as 'H-two-S'. Sites with H2S risk have fixed and personal gas detectors, wind socks and breathing apparatus, and staff take H2S training. Gas or crude containing H2S is called sour. Levels are given in ppm.
Examples
The alarm went off when H2S reached 10 ppm, and everyone moved upwind to the muster point.
Never rely on your nose to detect H2S.
Usage note
Spelled 'sulphide' in British and 'sulfide' in American English. H2S is heavier than air, so it collects in low places such as pits and cellars.
Common phrases
H2S alarm · H2S training · H2S detector · sour gas
A safety procedure in which equipment is switched off, isolated from its energy sources and fitted with personal locks and warning tags so nobody can start it during maintenance.
Where you use it
Usually called LOTO. Each worker puts their own lock on the isolation point and removes only their own lock at the end. Related words are isolation, energy sources, zero-energy state and 'try', which means testing that the machine cannot start.
Examples
Apply lockout/tagout on the conveyor before you clean under the belt.
He was injured because the lockout/tagout procedure was not followed on the pump.
Usage note
The term comes from US practice; in the UK people often speak of 'isolation' and 'lock-off' for the same idea.
Common phrases
lockout/tagout procedure · apply LOTO · isolation point · personal lock
A colourless, odourless gas (CH4) that is the main part of natural gas. In coal mines it is released from the coal and can explode when mixed with air.
Where you use it
Methane is explosive at about 5 to 15 percent in air, so coal mines monitor it continuously and cut the power when levels rise. Miners call the explosive mixture firedamp (Turkish: grizu). It is also a strong greenhouse gas, so leaks and venting are tracked.
Examples
Power to the face was cut automatically when methane rose above the limit.
Methane leaks from gas pipelines are a growing concern for regulators.
Usage note
Pronounced MEE-thane in British English and METH-ane in American English.
An electronic device that measures dangerous gases such as H2S, methane or carbon monoxide, or a lack of oxygen, and sounds an alarm when levels become unsafe.
Where you use it
Workers carry personal gas detectors (gas monitors) clipped to their clothing, and plants have fixed detectors linked to the control room. An area is gas tested before anyone enters a confined space. Detectors must be bump-tested and calibrated regularly.
Examples
Bump-test your gas detector at the start of every shift.
The fixed gas detector near the separator sent an alarm to the control room.
Common phrases
personal gas detector · fixed gas detector · four-gas detector · bump test · gas test
An enclosed area with limited ways in and out, such as a tank, vessel, pit or silo, where toxic gases or a lack of oxygen can make entry dangerous.
Where you use it
Entry needs a permit, gas testing, ventilation, an attendant at the entrance and a rescue plan. Many deaths happen when untrained people rush in to save a colleague, so 'never enter to rescue without the right equipment' is a core rule.
Examples
Nobody may enter the confined space until the gas test results are recorded on the permit.
The tank was classed as a confined space, so an attendant stayed at the manway.
Common phrases
confined space entry · confined space permit · confined space rescue · enter a confined space
A marked safe place where everyone must gather during an alarm or emergency so that supervisors can count people and see if anyone is missing.
Where you use it
Also called an assembly point; on offshore platforms people muster at lifeboat stations. The verb is 'muster': 'all personnel muster at point B'. Drills test how quickly everyone musters and is accounted for. Sites often have primary and secondary points, chosen by wind direction.
Examples
When the general alarm sounds, go to your muster point and report to the area warden.
Everyone was at the muster point within six minutes of the alarm.
Usage note
The phrase 'pass muster' (to be good enough) uses the same word but has nothing to do with emergencies.
Common phrases
muster drill · muster station · go to the muster point · head count
An unplanned event that could have caused injury or damage but did not, for example a dropped tool that lands next to a worker.
Where you use it
Companies encourage everyone to report near misses because they reveal hazards before someone gets hurt. You report, investigate and learn from a near miss. Safety statistics often show near misses alongside lost-time injuries (LTIs).
Examples
Please report every near miss, even if nobody was hurt.
A near miss on the drill floor led to new rules on dropped objects.
Common phrases
report a near miss · near-miss report · near-miss investigation · near-miss reporting
Short for health, safety and environment: the rules, people and systems a company uses to protect workers, the public and nature from harm.
Where you use it
Said as letters (H-S-E). Used in job titles (HSE manager, HSE advisor), documents (HSE plan, HSE policy) and meetings (HSE briefing). Variants include EHS, SHE and HSSE, which adds security. People say 'it's an HSE issue'.
Examples
Every visitor gets an HSE induction before going on site.
The HSE team stopped the job because the scaffold had not been inspected.
Usage note
Because the letter H is said 'aitch', write 'an HSE manager', not 'a HSE manager'.
The finely ground rock and water left over after the valuable minerals have been removed from ore in a processing plant.
Where you use it
Tailings are pumped as a slurry to a tailings storage facility (TSF), usually behind a tailings dam. Managing them safely is one of the biggest environmental and safety issues in mining; companies report on tailings volumes, dam stability and water recycling.
Examples
The tailings are thickened to recover water before they go to the dam.
Some mines now filter their tailings and store them as dry stacks.
Usage note
It is a plural noun: say 'the tailings are', not 'the tailing is'.
An accidental release of crude oil or oil products into the sea, rivers or onto land, for example from a tanker, pipeline or well.
Where you use it
Companies prepare oil spill response plans and keep equipment such as booms and skimmers. News reports give the size of a spill in barrels or tonnes and describe the clean-up. Small leaks on site are often just called spills and must be reported.
Examples
Booms were placed around the tanker to contain the oil spill.
The company tests its oil spill response plan in a drill twice a year.
Usage note
'Spill' is also a verb (oil spilled into the river). The past form is 'spilled' in US and UK English, and also 'spilt' in British English.
Common phrases
oil spill response · contain an oil spill · clean up an oil spill · major oil spill
Burning unwanted natural gas through a tall pipe called a flare at a well site, platform or plant, either for safety or because the gas cannot be used or sold.
Where you use it
Routine flaring wastes energy and adds CO2 emissions, so many companies and governments aim to end it, though safety flaring during upsets is still needed. People talk about flare stacks and flared volumes. Venting means releasing gas without burning it, which is worse for the climate.
Examples
Flaring increased during the compressor shutdown.
The project will capture associated gas and end routine flaring at the field.
Common phrases
gas flaring · routine flaring · flare stack · flaring and venting
A formal study of how a planned project such as a mine, pipeline or refinery will affect air, water, land, wildlife and local communities, and how those effects will be reduced.
Where you use it
Usually called an EIA; when social effects are included it may be called an ESIA. It is prepared by consultants, discussed at public meetings and approved by the authorities before construction starts. International lenders often require it to meet their own standards.
Examples
The environmental impact assessment for the mine expansion was approved by the ministry.
Local people were invited to a public meeting on the environmental impact assessment.
Common phrases
carry out an EIA · EIA report · EIA approval · public consultation
An embankment built to hold mine tailings and water in a storage area. If it fails, a flood of mud can destroy villages and rivers downstream.
Where you use it
The formal term is tailings storage facility (TSF). Engineers talk about dam raises, freeboard, seepage, piezometers and stability monitoring. Failures such as Brumadinho in Brazil in 2019 led to the Global Industry Standard on Tailings Management (GISTM) in 2020.
Examples
Piezometers in the tailings dam are read every week.
The tailings dam will be raised by five metres next year.
Common phrases
tailings storage facility (TSF) · dam raise · dam failure · dam safety review
Returning land disturbed by mining or drilling to a safe, stable and useful condition, for example by reshaping waste dumps, spreading topsoil and planting vegetation.
Where you use it
Also called rehabilitation, especially in Australia and the UK, or restoration. Mines prepare a closure and reclamation plan and often post a financial bond to guarantee the work. Progressive reclamation means restoring areas while mining continues elsewhere.
Examples
Reclamation of the old waste dump will start once mining moves to the east pit.
The company planted 50,000 trees as part of its reclamation programme.
Usage note
'Land reclamation' can also mean creating new land from the sea, so check the context.
Common phrases
mine reclamation · reclamation plan · progressive reclamation · reclamation bond
Acidic, metal-rich water that forms when sulphide minerals such as pyrite in mine waste or workings meet air and water. It can pollute rivers for decades.
Where you use it
Also called acid rock drainage (ARD). It is one of the most serious long-term environmental problems in metal and coal mining. Engineers test waste rock for its acid-generating potential, cover reactive waste and treat the water, for example with lime.
Examples
Acid mine drainage from the abandoned mine has turned the stream orange.
The treatment plant neutralises acid mine drainage with lime before the water is released.
Common phrases
acid rock drainage (ARD) · treat acid mine drainage · acid-generating waste · water treatment
Safely shutting down and removing an oil and gas facility, platform, pipeline or plant at the end of its life, including plugging the wells and cleaning up the site.
Where you use it
A major issue in mature offshore basins such as the North Sea. The work includes plug and abandonment (P&A) of wells, removing topsides and jackets and making the seabed safe. In mining, the similar stage is usually called mine closure.
Examples
Decommissioning of the platform will take three years.
The company has set aside funds for decommissioning its North Sea fields.
Usage note
The opposite is 'commissioning', which means testing new equipment and starting it up for the first time.
Common phrases
decommissioning costs · decommissioning plan · plug and abandonment (P&A) · mine closure
Describing the first stage of the oil and gas business: finding hydrocarbons, drilling wells and bringing oil and gas to the surface.
Where you use it
Used in company profiles, job ads, strategy reports and news: upstream sector, upstream operations, upstream company. It also works as a noun, as in 'she works in upstream'. The short form E&P (exploration and production) means the same thing.
Examples
After ten years in upstream operations, he moved to a job at a refinery.
Upstream investment usually falls when oil prices drop sharply.
Usage note
In mining, 'upstream' has another meaning: an upstream tailings dam is raised in steps on top of tailings deposited earlier.
Describing the last stage of the oil and gas business: refining crude oil, then distributing and selling fuels and other products to customers.
Where you use it
Covers refineries, petrochemical plants, fuel terminals and filling stations. Common in annual reports and market analysis: downstream business, downstream margins, downstream assets. Integrated companies are active both upstream and downstream.
Examples
Weak downstream margins hit the company's profits this quarter.
Our downstream division runs two refineries and a network of fuel stations.
Usage note
In a process plant, 'downstream of the valve' simply means further along the flow; the word is not only about business sectors.
The standard unit for measuring crude oil, equal to 42 US gallons or about 159 litres. Oil prices and production rates are quoted per barrel.
Where you use it
Abbreviated as bbl. Production is given in barrels per day (bpd or bopd), and prices in dollars per barrel. Large volumes are written as Mbbl or MMbbl (thousand or million barrels). Gas is sometimes converted to barrels of oil equivalent (boe).
Examples
The field is producing 12,000 barrels per day.
Brent was trading at around 80 dollars a barrel this morning.
Usage note
Oil is rarely moved in real barrels today; the word is a unit of volume. When reading aloud, 'bbl' is said as 'barrels'.
Common phrases
barrels per day · price per barrel · barrel of oil equivalent · million barrels
The amount of oil, gas or ore that is known to exist and can be produced at a profit with current technology and prices, estimated under set rules.
Where you use it
Used in the plural. Oil and gas reserves are classed as proved, probable and possible (1P, 2P, 3P). In mining, ore reserves are proven or probable and come from the larger mineral resources. Companies 'book', 'replace' and 'report' reserves.
Examples
The company's proved reserves rose by 8 percent after the new discovery.
At current production rates, the mine's reserves will last another twelve years.
Usage note
Reserves are not the same as resources: resources include material not yet shown to be economic. Mixing them up in a report is a serious mistake.
A payment that a producing company makes to the owner of the resource, usually the state, calculated as a share of the value or volume of the oil, gas or minerals produced.
Where you use it
Usually given as a rate, such as a royalty of 12.5 percent. Royalties are paid on production, unlike income tax, which is paid on profit. Private royalty holders also exist, and mining companies sometimes sell royalties to raise money.
Examples
The company pays a royalty of 12.5 percent on all oil produced from the licence.
Higher royalty rates could make the project uneconomic.
Usage note
In music and publishing, 'royalty' means the fee paid to an author or artist (telif ücreti). In oil, gas and mining it is a payment for the resource.
A contract in which the state keeps ownership of the oil or gas, the company pays for exploration and development, and production is shared between them after the company's costs are recovered.
Where you use it
Also called a production sharing contract (PSC). Key terms are cost oil (the share that repays the company's costs) and profit oil (the rest, split between the state and the company). It is an alternative to a licence and royalty system.
Examples
Under the production sharing agreement, the state takes 60 percent of profit oil.
The company signed a production sharing agreement for an offshore block.
Common phrases
sign a PSA · cost oil · profit oil · production sharing contract (PSC)
A blend of crude oils from the North Sea whose price is the main international benchmark for pricing oil around the world.
Where you use it
News reports and contracts quote Brent in dollars per barrel, and other crudes are priced at a premium or discount to it. The main US benchmark is WTI (West Texas Intermediate), and Dubai/Oman is used for Middle Eastern crude sold to Asia.
Examples
Brent crude rose 2 percent after the supply news.
Our crude is sold at a two-dollar discount to Brent crude.
Usage note
Brent takes a capital B because it is a name: it comes from the Brent oil field in the North Sea.
Common phrases
Brent futures · discount to Brent · premium to Brent · benchmark crude · WTI
Describing the middle part of the oil and gas business, which moves and stores oil and gas between the field and the refinery or market through pipelines, tankers, terminals and tanks.
Where you use it
Covers pipelines, gas processing plants, LNG terminals, storage and shipping. Midstream companies earn fees for moving volumes, so they talk about throughput, tariffs and long-term capacity contracts. Some companies count gas processing as midstream, others as upstream.
Examples
The midstream business earns steady fees from its pipelines and storage tanks.
After the merger, the company became one of the largest midstream operators in the region.
A detailed technical and financial study that shows whether a mine or an oil and gas project can be built and run at a profit, used to decide whether to invest.
Where you use it
In mining, studies usually go from a scoping study (or PEA) to a pre-feasibility study (PFS) and a definitive feasibility study (DFS). They estimate capital cost (capex), operating cost (opex), NPV and IRR. A positive study leads to a final investment decision (FID).
Examples
The feasibility study shows a mine life of 14 years and an NPV of 420 million dollars.
The banks will not lend until the definitive feasibility study is complete.
Common phrases
pre-feasibility study (PFS) · definitive feasibility study (DFS) · complete a feasibility study · feasibility study results
Ten questions from this glossary. Pick the right meaning for each term and see your score.
How to learn oil, gas & mining vocabulary
Start with the big picture: upstream, midstream and downstream in oil and gas, and the chain from exploration and mining to processing and closure in mining. Knowing where a word belongs in the chain makes it easier to remember.
Read real texts from the field: daily drilling reports, production reports, mine safety procedures, company annual reports, environmental impact assessments and published accident investigation reports. They show how the terms are used in context.
Learn abbreviations together with their full forms: BOP, H2S, PPE, LNG, HSE, EIA, FPSO and bbl appear in almost every report, email and meeting.
Practise numbers and units aloud: barrels per day, cubic feet of gas, tonnes, grams per tonne, ppm and psi. A wrong unit in a report can be a costly mistake.
Learn safety phrases exactly as they are used on site, such as 'stop the job', 'isolate the equipment' and 'go to your muster point'. In an emergency, short and standard English is the safest.
Frequently asked questions
Does the English word 'petrol' mean the same as Turkish 'petrol'?
No. In British English 'petrol' is the fuel you put in a car, called 'gasoline' or 'gas' in American English. For Turkish 'petrol' in the industry sense, say 'oil' or 'crude oil': a 'petrol şirketi' is an 'oil company' and a 'petrol kuyusu' is an 'oil well'.
What is the difference between upstream, midstream and downstream?
They are the three parts of the oil and gas value chain. Upstream is exploration and production: finding oil and gas and bringing it to the surface. Midstream is moving and storing it through pipelines, tankers, terminals and tanks. Downstream is refining it and selling fuels and petrochemicals to customers. Companies active in all three are called integrated companies.
What is the difference between resources and reserves?
Resources are the total amount of oil, gas or minerals thought to exist, including material that may never be economic to produce. Reserves are the part that can be produced at a profit under current conditions and has been assessed under reporting rules, such as SPE-PRMS for oil and gas, or the JORC Code, NI 43-101 and Turkey's UMREK Code for mining. Treating the two words as synonyms in a report is a serious mistake.
Which units should I know for oil, gas and mining English?
Oil is measured in barrels (1 barrel = 42 US gallons, about 159 litres) and production in barrels per day. Gas is measured in cubic metres or cubic feet, often in thousands (Mcf), millions (MMcf) or billions of cubic metres (bcm). Mining uses metric tonnes, grades in percent or grams per tonne (g/t), and troy ounces for gold. Pressure is usually given in psi or bar.
Do Turkish professionals in this sector use English terms at work?
Yes, very often. On rigs, platforms and international mining projects, words such as BOP, casing, kick, pig, flare, LOTO and HSE are usually kept in English, even in Turkish conversation, and reports for foreign partners, lenders and contractors are written in English. Knowing both the English term and its Turkish equivalent helps you work with local teams and international partners.
