Down a modern mine
Our deep mines are amongst the deepest in the world and have the most advanced underground equipment available.
Modern mining makes extensive use of computers; a single powered roof support will have three microcomputers managing its automated functions. Surface control rooms have instant access to real-time data from any part of the mine allowing any problems or potential hazards to be identified and addressed quickly and safely.
On the surface of a modern deep mine, the control room is able to monitor most of the activities being carried out underground. This includes transport systems, the movement of coal on conveyor belts and coal cutting activities. The control room is also able to monitor the underground environment and constantly checks critical factors such as mine gas concentrations, ventilation and temperature readings.
This gives the control room, and managers, almost total visibility of all activities underground.
An illustration depicting a typical deep mine layout and machinery used.
Preparing to enter the mine
Safety is taken extremely seriously in all aspects of deep mining. Miners now wear a large amount of personal protective equipment which includes a helmet, ear defenders, kneepads, shin pads, gloves, safety glasses, battery-powered lamp and a self-rescuer.
Of these items, the self-rescuer is the least likely to be used but is essential as it provides the capacity to breathe in the event of an underground fire.
Miners swipe their 'pass cards' before going underground to register their presence in the mine. Before entering the cage to descend into the mine, there is a further check to ensure that no combustible 'contraband' (such as cigarettes, matches or aluminium foil), enters the mine.
The miners enter a steel cage which descends down the mineshaft at speeds of three metres per second. Our coal mines are some of the deepest in the world at depths of between 700 to 850 metres.
Travel (1, 2 & 3)
Having completed their descent, most miners will board a train hauled by a diesel or battery-powered locomotive which will take them to the districts currently being worked in the mine. They may also walk, drive using four-wheel vehicles know as 'drift runners' or travel by conveyor belts designed for people to ride on.
Coal extraction began near to where the shafts were originally sunk and extended further outwards to reach new coal resources over the years. Miners may often be working more than 8km from the bottom of the shaft and their journey underground can take up to 90 minutes.
The coalface (4, 5 & 6)
At the coalface itself, miners work under the protection of 'powered roof supports' which support the roof as coal is cut from the seam. These also provide protection for the coal-cutting machine, known as a 'shearer', which moves backwards and forwards along the coalface cutting the coal.
As the shearer travels along the coalface, the powered roof supports advance into the gap created ready for the shearer to make a return run along the coalface. The average coalface is between 300m and 350m in length and produces up to 2,000 tonnes of coal per cut.
The cut coal falls onto an 'armoured face conveyor' which takes the coal away from the coalface. During this process coal dust is kept to a minimum by the use of water sprays.
The coal is taken to the bottom of the shaft on a series on conveyor belts and loaded into 22.5 tonne skips to be taken up the shaft to the surface.
Once on the surface the coal is washed and prepared for our customers in coal preparation plants.
Creating new coal panels (7, 8)
To be able to cut the coal from a coalface, roadways have to be driven through the strata to create a panel of coal. This is usually around 1,000 - 2,000 metres in length and 250 - 300 metres in width, and becomes the next coalface to be mined.
To create these panels we use two different types of cutting machines. One has a rotating head fitted at the end of a boom and is used to create the arched roadways that are used as the main colliery transportation routes.
The second has an elongated cutting drum the same width as the machine and cuts out a rectangular-shaped roadway that is normally supported by roofbolting. This type of machine is usually employed to develop access routes to the coalface.