Mining
Mining has a tradition of several thousand years and is still an important economic field for many regions. The mined raw materials are divided into three major groups: Elementary raw materials (including ores, salts, sulphur), energy raw materials (crude oil, natural gas, brown and black coal, uranium, etc.) and property raw materials (stones and earths).
Oil and natural gas are energy sources just like brown and black coal. Brown coal is mainly used to generate electricity in power plants, while black coal is processed into coke to be used as fuel and reducing agent in blast furnaces for iron production. Peat combustion for heat generation can also be found in marshlands. All these materials are based on plant biomass, which is compacted and converted under high pressures and temperatures. The carbon content determines the distinction between peat (60 %), brown (70 %) and black coal (84 %).
The production method is selected according to the location and potential of the deposit. Open-cast mining is used for extracting near-surface raw materials, such as brown coal. Underground and seam-like deposits such as black coal are exploited in mines, while crude oil, natural gas or brines in salt mines are extracted via deep boreholes.
All mining and mineral processing operations run under harsh environmental conditions. The atmosphere underground is explosive, with large amounts of dust and gas leaks. Additionally, dirt, humidity and heat do their part. In open pit mining, on the other hand, temperatures are often below zero. Both methods of raw material extraction transport large quantities of groundwater over long distances and also move mixtures of water, waste and minerals.
Machines that break up and strip coal seams underground must be protected against thermal overload. The demand for dust-binding, cooling and drainage systems is high. Such specific environmental conditions require materials that are resistant to high temperatures and frost as well as robust, reliable and low-maintenance valves with ATEX approval.
