Velenje Mining Method 

Velenje Mining Method was first introduced in 1947. In the technological and organisational sense, it is still developing and improving, especially in terms of increasing production from one excavation panel, layer recovery, safety of employees, humanisation of work and economy.

Due to its specific nature and high productivity, the Velenje Mining Method is known around the globe and is listed as an independent term (Velenje Mining Method) in professional mining literature. Patent-protected, it is described as a “Method of extraction of coal, particularly from thick coal seams” (patent number 9500091). The basic approach with this method is expanding the extraction site above the protected area (above the roof supports) and thus exploiting the natural forces of breaking and crumbling of the coal layer.

In terms of height, the coalface is divided into the footline section and the hanging wall section. The footline section is 3 to 4 m high and secured by a hydraulic support system, which allows mechanised exploitation by using excavation machinery (shearer loaders) and the conveyance of coal by using efficient chain conveyors. The hanging wall section, measuring 7 to 18 m, is exposed to dynamic stress conditions, which cause the crumbling of the coal layer. The crushed coal is then poured onto the conveyor in a controlled way and promptly transported to the surface.

The allowed excavation height depends on the thickness of the clay insulating layer in the above the coal seam, which protect the face from the inrush of running sand and water. 

A distinctive feature of the Velenje Mining Method is the procedure of controlled winning of roof coal by ‘pouring’ over roof supports into the longwall chain conveyor, which provides very high production capacity with an extremely high level of safety and economic return.

The basic parameters of the excavation technology are:

  • excavation length: 140–170 m (max. 220 m),
  • excavation height: 4–18 m,
  • excavation progress: 3–8 m/day,
  • daily production on one excavation: 3,000–10,000 t/day,
  • productivity: 40–60 t/m/day,
  • extraction efficiency: 110–160 t/day,
  • annual extraction: 3.5 million tonnes/year (max. 5.1 million tonnes in 1985).