Category Archives: News

Long Wall Mining

Long wall mining is the most productive technology in the world,where one shearer is deployed in one mine for producing coal up to 1 million-3million tons per annum from a single face.The advantage of the system is that it has very low manpower requirement.It can work in very high gradient working and has the lowest cost of production mainly on the account of high output.This is also one of the safest mining operations.

In this system,the coal is developed by gate road on the both sides of the long wall and is recovered with shearer system with power pack support and coal evacuation system.

Long wall mining has its own disadvantages with context to the Indian mining industry.The following are some of them:

(i)The coal seams should be free of any geological disturbances and since Indian seams are highly  geologically disturbed,deployment of such system fail;

(ii)It can a highly capital intensive technique;

(iii)It cannot be done without back filling with sand.A heave buildup structure  and habitats on the surface make it impossible to work by this method.

In place of a typical long wall technology with face length of around 250 meters,a short face length of around 40-90meters is adopted in Balrampur Colliery of SECL.

The short wall technology is a smaller version of the long wall.This has a small wall for cutting (50-100meters)in place of more than 250 meters in conventional long wall.The capital cost is small.In smaller capacity short wall,the stowing can also be done to manage subsidence in case of structure buildup on the surface.

ELECTRICITY GENERATION

The share of generation fueled by coal in the US has declined dramatically in recent months.Coal’s share of total power generation first fell below 40 percent in November last year and averaged 36 percent during the first quarter of 2012,compared with an average of almost 45 percent during the same period last year.

Much of this reduction has resulted from the decreased utilisation of exciting coal-fired capacity,including some capacity that is scheduled to be retired during the next few years.

The reduction in coal generation has been offset by increased utilisation of natural gas combined cycle plants.EIA expects that the higher natural gas costs projected later in 2012 and in 2013,along with record coal stocks,will encourage generators to increase their utilisation of coal-fired power plants next year.

After a projected decline of 13 percent in 2012,EIA forecasts total generation by coal across all sectors to rise by 3 percent in 2013.

In contrast,total generation by natural gas is forecast to rise 22 percent this year and then rise by less then 1 percent in 2013.