Glossary of mining terms
Anemometer: a handheld device used to measure air velocity.
Apparatus or rescue breathing apparatus (RBA): A closed-circuit respiratory protective device that provides an independent oxygen source for individuals who are expected to work in environments containing toxic air contaminants, such as carbon monoxide. The device weighs about 35 pounds and is carried on the emergency responder’s back. RBAs provide about four hours of service, compared to the typical self-contained self-rescuers (SCSR) used by most US miners, which provide less than one hour.
Barrier Section at UBB: a continuous miner section located off of the North Mains between Headgate 16 and Headgate 17, near the north portal. HG16 and HG17 were previous longwall mining sections and the mine operator was trying to recover the remaining coal between the two gob areas.
Belt/Conveyor Belt: A belt used to carry the mined coal and rock; power cables are run along with the belts.
Black Hat: A miner who is no longer an apprentice, but a fully certified underground coal miner.
Brattice: A board or other partition used in a mine passage to confine the air and force it into a particular working section. If not installed and used properly, intake air will short circuit into the return airway.
Brattice Cloth: Fire-resistant canvas or duck cloth used to erect a brattice and temporarily force air to flow in a particular direction.
Break: The distance between coal pillars. Break distances vary from mine to mine depending on geology and the type of mining used. At UBB, the break distances were 105 ft or 120 ft from center to center.
CFM: a measurement of air in cubic feet per minute.
Connector section/Crossover panel: A stretch of track which connects two parallel tracks, and enables a mantrip or vehicle to pass from one track to the other.
Continuous Miner: A mining machine designed to remove coal from the face and load it into shuttle cars or conveyors without the use of drills or explosives.
Cowl Blade: a metal, half moon shaped component that covers the cutting drum of the shearer on a longwall mining machine. There is one cowl for each drum. The cowl helps control the coal, rock, and debris generated from the cutting action of the drums.
Curtain (mine curtain/check curtain): A sheet of brattice cloth, often coated with fireproofing, hung across an entry to prevent the passage of an air current, but not to hinder the passage of equipment or vehicles. Curtains are used to deflect the air from the entries into the working sections and to hold the air along the faces.
D2 order: refers to section 104(d)(2) of the Mine Act (30 USC 801 et seq.) If a mine operator has received a violation for an unwarrantable failure to comply with a mandatory standard that could significantly and substantially contribute to a hazard, and on a subsequent inspection the inspector finds the same violation, a D2 order is issued to withdraw miners from the affected area.
Date-up board: Usually made of a piece of belting or designed to the mine operator’s specifications by a vendor, date-up boards are placed at specific locations in airways, belt lines, track entries or even near the working faces for mine examiners to record the date, time and initials to indicate when they made their required examination of the area.
Dewatering pumps: Pumps used to remove water from a mine.
Drift: a horizontal opening into a coal mine; miners and supplies enter at the drift; also can provides a source for ventilation.
Ellis Portal: One of the Upper Big Branch mine portals where miners and equipment entered and exited. The Ellis portal had five drift entrances and was relatively new compared to the other UBB portals. Typically, the longwall, HG22 and TG22 crews began and ended their shifts at the Ellis portal.
Ellis Switch: An area in the Upper Big Branch mine where a device was located that enabled a mantrip or other vehicle to pass from one track to another.
Face: The solid surface of the unbroken portion of the coal bed at the advancing end of the working section.
Fan: A mechanical piece of equipment that is powered by electricity that can provide either fresh air to a mine or pull return air out of a mine. Fans are either set on top of a shaft or sit in a drift opening.
Fresh air: Air sent into an underground mine containing not less than 19.5% oxygen, not more than 0.5% carbon monoxide and no harmful quantities of other noxious gases.
Fresh Air Base (FAB): An area in the mine established by mine rescue teams in which breathing apparatus do not have to be worn, and where supplies and equipment are located. It is the base camp or safe area for the mine rescue teams deployed underground. It is where backup mine rescue team members assemble to replace other teams, or respond in case a team member goes down. The FAB serves as communication link between teams underground and the command center on the surface. As the mine is explored during an emergency situation, and the teams determine that they can proceed further inby without the need of breathing apparatus, the fresh air base can be moved deeper into the mine.
Gob: An area of the mine where coal has been extracted and the top allowed to fall down. The area behind a set of longwall shields, for example, is referred to as the gob.
Headgate (Longwall Headgate): The start of the longwall face. As coal is extracted, the longwall travels to the headgate where it is dumped on to a stage loader conveyer. Coal travels through a crusher and is dumped onto a rubber conveyer belt. The first shield (shield #1) in the line of shields across the face is located at the stage loader, along with electrical and water disconnects, drive motors and phone communications. Fresh air to ventilate the longwall face enters the longwall section at the headgate.
Headgate 22 Section: A continuous miner section in the UBB mine where crews were driving the headgate entries for a new longwall panel.
Hinge pin: As used in this report, metal pins that are used to attach the ranging arm to the shearer.
Hot Seating: A term referring to a system of shift changing when an oncoming crew of workers comes onto the work section just as the crew they are replacing departs.
Inby: Toward the working face, or interior of the mine; away from the portal (entrance).
Kennedy stoppings: a stopping which uses tin panels as its major component; usually for temporary use.
LFM: a measurement of air in linear feet per minute.
Longwall: A method of extracting coal seams from a long working face. As the workings advance in a continuous line, which may be several hundreds of yards in length, space from which the coal has been removed is either allowed to collapse or is completely or partially filled or stowed with stone and debris.
Longwall Shields: At UBB the longwall mining machine had 176 shields, roof shields or supports, each measuring 1.75 meters wide (or about 5.74 feet.) One “pass” on the longwall is a complete trip by the shearer from shield #1 to shield #176; a second “pass” would be the return trip from shield #176 to shield #1.
Mandoor: Metal doors that are placed in stoppings for miners to go from one entry to another. There are single mandoors and there are walk-through doors that are used to allow not only workers but also supplies to pass through them. When closed, the doors maintain the integrity of the ventilation system.
Mantrip: A vehicle on a track used to take miners to and from the working places. Due to the low ceilings in mines, mantrips tend to be of reduced height.
Methane: (CH4 ) formed by the decomposition of organic matter; a tasteless, colorless, and odorless gas; highly explosive in concentrations of 5-15 percent of ambient air.
Methane Detector: an electronic device used to measure the percentage of methane in the air.
Mother Drive: a belt drive that powers the coal conveyor belt. In the UBB, a mother drive was located in the North Glory Mains at Break #102.
Multi-gas Detector: a handheld electronic device that can measure percentages of methane, carbon monoxide and other air contaminants.
Outby: Away from the mining face; toward the mine entrance.
Omega Blocks: a lightweight material shaped in the form of a cement block used to construct stoppings.
On shift examination: A required examination under MSHA regulation 30 CFR § 75.362 stipulating that at least once during each shift, or more often if necessary for safety, a certified person designated by the operator must exam any areas where miners are assigned to work and/or where mechanized mining equipment is being installed or removed. The certified person is expected to check for hazardous conditions, test for methane and oxygen deficiency, and determine if the air is moving in the proper direction.
Overcast: An enclosed airway to permit one air current to pass over another one without an interruption. Overcast are built of incombustible materials, such as concrete, tile, stone or brick.
Pre-shift examination: A required examination under MSHA regulation 30 CFR § 75.360, stipulating that a certified person designated by the operator make an examination within 3 hours preceding the beginning of any 8-hour interval during which any person is scheduled to work or travel underground.
Portal: Entrance to the mine; see also Ellis Portal.
Power Center: See mother drive.
PSI: pounds per square inch.
Punch out: Punch out or punching out refers to the point when a continuous mining machine or a longwall shearer cuts into another entry or cross-cut. In the case of a longwall, when the shearer reaches the tail or the end of the block of coal, the term “cutting out” may be used. Punch out can also refer to the portal.
Pyott-Boone Electronics: A Virginia company providing communication, tracking and other electronic products to the mining industry. The tracking and communication system used at UBB was a Pyott-Boone system.
Ranging Arm: A large metal component attached to the body of the longwall shearer. There is a ranging arm with a cutting drum on both the head side and tail side. The ranging arm rises up and down to cut coal and its motion is controlled by miners known as shearer operators.
Red Hat: An apprentice miner; he or she wears a red hardhat. Under WV mine safety regulations, a red hat can earn a black hat after six months and more than 108 days working underground, as well as passing a written test.
Regulator: An adjustable opening in a stopping that is used to control air quantity.
Return air: Air that has already ventilated a working area of a coal mine.
Rib fall: A rib fall occurs when the rib, or coal wall of an entry or cross-cut, falls out into an entry; brought on by geologic pressures or weak or fractured coal seams. When the coal wall slides to the mine floor instead of out into an entry, it is referred to as sloughing.
Roof fall: A roof fall is when the mine roof or top falls to the mine floor; some are intentional, others are unintentional and caused by unsupported top or insufficient roof support. During longwall mining, roof falls occur behind the shields and are considered intentional roof falls.
Seals: Block walls constructed according to strict performance standards in order to withstand a specific amount of pressure. Seals separate abandoned workings from active workings.
Self-Contained Self Rescuer (SCSR): A respiratory device carried by miners at all time and used during an emergency to provide a supply of oxygen for up to 60 minutes.
Shaft: A vertical opening that connects the surface to the underground workings of a coal mine.
Shearer/shearing machine: An electrically-driven machine for making vertical cuts in the coal.
Shield: A framework or screen of wood or iron protecting the workers on a longwall; shields push forward as the coal is cut.
Sloughing: See rib fall.
Stage Loader: See mother drive.
Starter Box (Longwall Starter Box): Located on the headgate side of the longwall; it is where electrical motors are positioned that power the longwall.
Stopping: A ventilation control that is used to separate fresh air from return air; some are temporary, others are permanent; built across old airways, headings, or entries, to confine the ventilating air current to certain passages.
Swing Shift: When a miner works one shift for a continuous set of days (e.g., day shift) and then swings to a different shift (e.g., night shift) for the next consecutive set of days.
Switch: A device for enabling a car or a mantrip to pass from one track to another.
Tailgate (Longwall Tailgate): This is the end of the longwall face; the last shield is at the tailgate. At the tailgate there is a tail drive, an electrical motor that helps power the face conveyer chain. Air that has already ventilated the longwall face exits at the tailgate and goes in to another air course.
Tailgate 22 Section: A continuous miner section in the UBB mine where crews were driving the tailgate for a new longwall panel.
Ventilation: The directing and controlling of air usually provided by mechanical means to an underground coal mine.
Primary Source: Dictionary of Mining, Mineral and Related Terms. Washington, DC: Department of the Interior, Bureau of Mines, 1968.