Structure of a Coal Mine

The following interactive 3D model shows a schematic representation of a hard coal mine with its most important surface and underground components. By clicking on the colour-highlighted objects, information about the respective component is displayed.

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Description

The 3D model depicts a typical hard coal mine as commonly found in the Ruhr area and other European coalfields. The installation comprises both the surface facilities (pithead buildings) and a simplified representation of the underground extraction. The viewer can freely rotate, zoom and pan the model to explore the spatial arrangement of the components.

By clicking on the colour-marked objects, a description of the respective component is displayed. This allows the material flow to be traced from coal extraction at the longwall face, through haulage up the shaft, to processing in the coal washing plant.

Components of the Mine

The following table provides an overview of the components shown in the model and their function in the operational sequence of a hard coal mine.

ComponentDescription
HeadframeStands above the shaft and supports the sheave wheels for the winding rope. Enables vertical transport of personnel, materials and raw coal between the surface and the underground levels.
Engine HouseHouses the winding engine, which moves the cages or skips up and down the shaft via a steel rope.
Coal Washing PlantSeparates the extracted raw coal from the surrounding rock by exploiting the difference in density, using dense-medium separators or jig washers.
Changing HouseWashing and changing facility for the miners, divided into a clean side (street clothes), a dirty side (work clothes) and a washroom.
Ventilation ShaftServes to ventilate the underground workings. Fresh air flows in and stale air is extracted – essential for diluting firedamp (methane).
Mine DrainagePumps remove groundwater that seeps in from the surrounding rock. Without them, the mine would flood.
Coal PloughPulled along the coal face by a chain, it shears thin chips from the seam. Mainly used in thin seams.
Drum ShearerCuts coal from the seam using rotating drums fitted with cutting picks. Used in thicker seams and achieves higher output than the coal plough.

Interactive Controls

The 3D model can be controlled with the following inputs:

  • Rotate: Hold down the left mouse button and drag
  • Zoom: Scroll the mouse wheel or use a two-finger gesture on the touchscreen
  • Pan: Hold down the right mouse button and drag
  • Select object: Click on a colour-highlighted object to display its description

Technical Background

Hard coal mining requires the complex interplay of numerous surface and underground operating facilities. Coal is extracted at the longwall faces – the actual mining areas – and transported to the shaft by chain conveyors and belt systems. From there it is brought to the surface by the shaft winding system, where it is processed in the coal washing plant and classified for sale.

Underground safety depends crucially on the ventilation and drainage systems. Ventilation supplies fresh air to the underground workings and dilutes explosive gases such as methane (firedamp), which is naturally trapped within the coal seams. Mine drainage prevents the deep workings from flooding by removing the groundwater that seeps in from the surrounding rock.

History of Coal Mining in the Ruhr Area

Coal mining in the Ruhr area looks back on a history spanning more than 750 years. As early as the 13th century, coal was extracted near the surface along the River Ruhr – initially by simple drift mining, where horizontal tunnels were driven into hillsides. With industrialisation in the 19th century, deep mining began: vertical shafts opened up ever deeper seams, and output rose rapidly.

At its peak around 1956, more than 140 collieries in the Ruhr area produced approximately 125 million tonnes of hard coal per year. Over 600,000 miners worked in the region. From the 1960s, the coal crisis set in – cheap imported coal and the rise of oil and natural gas made domestic mining increasingly uneconomical.

On 21 December 2018, the last shift at Prosper-Haniel colliery in Bottrop marked the end of active hard coal mining in Germany. What remains are the so-called perpetual obligations: the permanent drainage of the disused mines, the securing of shafts and the treatment of mine water.

The Journey of Coal – from Seam to Dispatch

The material flow in a hard coal mine follows a fixed sequence:

  1. Extraction at the longwall face: The coal plough or drum shearer cuts the coal from the seam. The longwall face is the actual extraction area – a long, low front along the coal seam.
  2. Face conveyor: An armoured face conveyor (AFC) collects the loosened coal and transports it to the end of the longwall face.
  3. Gate road conveyors: Belt conveyors take over the coal and transport it through the gate roads to the pit bottom at the shaft.
  4. Shaft winding: At the pit bottom, the coal is loaded into winding vessels (skips). The winding engine in the engine house hauls them up the shaft to the surface via the winding rope.
  5. Coal washing: At the surface, the raw coal is separated from the waste rock in the coal washing plant and sorted by grain size and quality.
  6. Dispatch: The processed coal is loaded onto railway wagons, barges or lorries and delivered to power stations, steelworks or the trade.

Safety Underground

Working underground has always involved considerable hazards. The most important safety systems of a mine are:

Ventilation

Ventilation is the mine’s air supply system. Large fans at the ventilation shaft generate a continuous airflow through all underground workings. This serves two vital purposes: it supplies the miners with breathable air and dilutes the firedamp (methane) escaping from the coal seams to safe concentrations.

Firedamp

When the methane-air mixture reaches a concentration between 5 and 14 per cent, it becomes explosive – known in mining as firedamp. Firedamp explosions were among the most devastating disasters in mining history. Continuous gas monitoring with electronic sensors therefore became a central element of mine safety.

Safety Lamp

Before the introduction of electric lighting, the Davy safety lamp (invented in 1815 by Sir Humphry Davy) was a groundbreaking invention. A fine wire gauze around the flame prevented it from igniting the surrounding firedamp. At the same time, the lamp served as a gas detector: if the flame changed in appearance, an elevated methane concentration was indicated.

Mine Rescue

For emergencies, mine rescue teams stood ready – specially trained crews with breathing apparatus who were deployed in the event of fires, explosions or collapses underground.

Glossary of Mining Terms

Mining has developed its own specialised vocabulary over centuries. Many of these terms remain in everyday use in coalfield regions.

TermMeaning
Seam (Flöz)A workable layer of coal within the rock strata
Longwall face (Streb)The active extraction area where coal is cut from the seam
Level (Sohle)A horizontal plane (storey) within the mine
Roadway (Strecke)A horizontal passage underground, comparable to a tunnel
Pit bank (Hängebank)The platform at the shaft top on the surface where cages are loaded and unloaded
Pit bottom (Füllort)The loading point at the shaft underground – the counterpart of the pit bank
Changing house (Kaue)The washing and changing building for the miners
Stint / Bargain (Gedinge)Performance-related pay for miners, negotiated between the overman and the work team
Overman (Steiger)A supervisor underground, comparable to a foreman or shift leader
Ventilation (Bewetterung)The supply of fresh air to the underground workings
Firedamp (Schlagende Wetter)An explosive methane-air mixture
Waste rock (Berge)Worthless rock produced alongside coal extraction
Spoil tip (Halde)A mound of waste rock deposited on the surface
Glück auf!The traditional miners’ greeting – originally a wish to strike a productive seam

Historical and Modern Mining Compared

The methods of hard coal mining have changed fundamentally over the centuries. The following overview compares the historical mining of the 19th century with the mechanised extraction of the 20th century.

AspectHistorical (19th c.)Mechanised (20th c.)
ExtractionManual work with pick and hammerCoal plough, drum shearer
Underground haulageHauliers and pit ponies pulled tubs on railsArmoured face conveyors and belt systems
Shaft windingSteam-powered winding enginesElectric winding engines
LightingOil lamps, later Davy safety lampElectric cap lamps
VentilationNatural draught, hand-operated fansElectric main fans
Roof supportWooden props and barsHydraulic powered supports (shields)
Working depthUp to about 500 mOver 1,000 m (up to 1,500 m in the Ruhr area)
Daily output per manApproximately 1 tonneOver 6 tonnes

Hard coal continues to be mined worldwide – predominantly, however, by cheaper opencast methods, as practised in Australia, Indonesia and parts of the USA. In countries such as China, Poland and South Africa, deep mining also remains active, albeit under increasing economic and climate-policy pressure.

For the Classroom

The interactive 3D model is suitable for use in a range of subjects and year groups. The following overview provides suggestions for integrating it into teaching.

Cross-curricular Links

  • Physics / Technology: Forces and mechanics of winding, the principle of density separation in the coal washing plant
  • Chemistry: Methane as firedamp, combustion, explosion limits
  • Geography: Mineral deposits, geology of the Ruhr area, structural change
  • History: Industrialisation, social history of miners, labour movement
  • Politics / Economics: Subsidies, energy policy, structural change, perpetual obligations

Key Questions for Students

  1. Describe the journey of coal from the seam to dispatch using the 3D model.
  2. Why does a mine need at least two shafts?
  3. Explain why ventilation is essential for the safety of miners.
  4. Compare historical extraction with pick and hammer to the use of a drum shearer. What are the advantages and disadvantages?
  5. What tasks remain after a mine is closed and why?

Coal in the Energy Economy

Hard coal was the fuel of the Industrial Revolution. From the mid-19th century, it replaced wood and charcoal as the primary energy source and powered steam engines, railways and steelworks. Without the coal of the Ruhr area, the industrialisation of Germany would not have been possible in this form.

Rise and Decline

In the post-war period, German hard coal mining reached its peak. From the 1960s, domestic coal increasingly lost competitiveness against cheaper imports and new energy sources (oil, natural gas, nuclear power). The state supported mining with subsidies for decades – an estimated total of over 300 billion euros flowed into the German hard coal industry.

Coal and Climate Policy

Burning hard coal releases large quantities of CO₂ and contributes significantly to climate change. As part of its energy transition (Energiewende), Germany has decided to phase out coal-fired power generation by 2038 at the latest. Renewable energies – wind, solar and hydropower – are intended to fill the gap.

Perpetual Obligations

Closing the mines does not end the work. Groundwater constantly seeps into the abandoned workings and must be pumped out to prevent it from rising to the surface and flooding residential areas. These perpetual obligations – mine drainage, polder measures and mine water treatment – will in all likelihood continue indefinitely and cost several hundred million euros per year. The RAG Foundation was established to finance these costs on a permanent basis.

Notes on the Model

The 3D model is a simplified, schematic representation. A real mine comprises numerous additional facilities, including workshops, stores, compressor stations, substations, rail systems and spoil tip installations. The underground representation is limited to the extraction equipment at the longwall face and does not show the complete mine layout with roadways, gate roads and staple shafts.

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