In February 2022, Anglo American announced, that Grasstree mine reached its end of life.
A longwall is a complex system of mining equipment that incorporates hydraulic roof supports (called ‘chocks’ or ‘shields’), coal cutting and coal transport equipment. Longwall mining involves extracting rectangular panels of coal, typically around 150 m to 400 m wide, up to 7 km long and 2 m to 5 m thick. Longwall panels are defined by access roadways that are constructed around the perimeter of each longwall panel. These roadways provide access for the installation of the longwall mining equipment, mine workers, and equipment and services.
Longwall mining involves a coal shearer travelling back and forth across the width of the longwall panel, starting from the furthest point progressively removing the coal from the panel back to the main headings. The shearer cuts the coal from the coalface on each pass and delivers the coal to a face conveyor that runs along the full width of the longwall. The face conveyor transports the coal from the coalface to another conveyor in an access roadway. Coal is then transported to the surface via a series of connecting underground conveyors.
The roof at the coalface is held up by a series of hydraulic roof supports. The supported section of roof provides space for the shearer, face conveyor and man access. After each shear of coal is removed, the face conveyor, hydraulic roof supports and the shearer are moved fo ........