Coal Mining Vs. Metalliferous Mining: Mining Engineers Dairy - Metalliferous Mines IndiaIn India, for purposes of mining legislation framed by the Government, minerals which cannot be called coal or lignite are classified as metalliferous minerals and they are governed by Regulations applicable to metalliferous mining. The differents between coal and metalliferous mining are as follows.
Coal is bedded deposit. Most of the metalliferous minerals are however, non-bedded type with the exception of limestones, potash, salt, iron, phosphates, etc.Bedded deposits normally have a large horizontal extent, and they are more uniform in thickness, quality and dip. They are often only mildly inclined; very steep or nearly vertical bedded deposits normally have a large horiaontal extent, and they are more uniform in thickness, quality and dip. They are often only mildly inclined; very steep or nearly vertical bedded deposits are not common. Mineral ore bodies are, as a rule, irregular in extent shape, thickness, quality and dip. In many cases they exist in patches or shoots. Hence metal mining methods are more varied and they coal drills are therefore electrically operated. In fact is the main power in underground metal mines. Extraction of coal is comparatively easy. Roof of coal is comparatively soft and crumbly.
Coal is softer than most of the metalliferous minerals and coal drills are therefore electrically operated. In fact electricity is the power in coal miens, wheras compressed air is the main power in underground metal mines. Extraction of coal is comparatively easy. Roof of coal is comparatively soft and erumbly.
Coal can be used directly after extraction from the mine as a fuel. Practically all the metallic minerals need to be processed for getting the mineral and the metal. Infrastructure in a metal mine is therefore heavy and costly.
Underground mining of coal is much simpler. After the vertical shaft touches a coal seam, the roads can be made in the coal seam itself (in the seam mining) producing coal in the process of drivage of roads. Hardly any roads or excavation is required in the roof or floor or stone of the coal seam as in our country, coal seams less than 1.5 m thick receive second preference for working. In metalliferous mining horizon mining is the standard practice requiring drivage of roads in the foot wall and a net work of other roads in the country rock to reach the orebody.
Underground coal mines produce an inflable and explosive gas, fire damp. Such danger does not exist in underground metal mines. Naked lights cannot therefore be used in coal mines which have to be worked with the help of flame safety lamps, permitted explosives, flame-proof machinery and other devices so as to protect against dangers of methane gas.
Sampling and assaying are important day-to-day operations in metalliferous mining during the development stage. Coal mining does not call for a regular team of workers for sampling and quality control. For the same reasons the geologist is an essential staff in a metal mine. Coal mines are known to have worked for years without the help of the geologists after initial exploration.
Metal mining requires a high standard of surveying. In coal mines where in-the-seam mining is practiced, as in 95% our mines, a slight error in marking the centre lines of galleries and roadways would, in any case, yield coal from the deviated road. In metal mines such error would result in blasting of unproductive rock, sometimes for long stretches.
Coal mining is amenable to large scale mechanization.
Metal mining involves more detailed exploration and creful planning before opening up a mine, particularly an underground mine. The gestation period for underground metal mine is comparatively longer, usually 4-5 years of which shaft sinking alone would take 2-3 years.