Highwall mining systems at surface coal mines in Indonesia

摘要

Indonesia is the second largest coal exporter to Japan, Almost all the coal is produced from open cut mines. However, a great deal of coal is left in the highwalls of the mined-out pits. The use of highwall mining systems has increasingly come into play in the USA and Australia, when overburden depth exceeds economical recovery in open cut mines. However, the stability of the highwalls is always a major safety concern in such mining. Here we look at the operational and geotechnical problems in highwall mining systems in Indonesia. Indonesia produces over 150 Mt of clean coal and is the second largest coal exporter to Japan, accounting for 30 Mt/y. Over 99 percent of the coal produced is from open cut mines. Naturally there are many sites where mining operations have developed long highwalls which have been abandoned due to the economics of the day. Mining operations have been transferred to lower stripping ratio blocks of coal or overlying seams. In some cases, coal lies buried beneath spoil heaps or is covered with mud and water. It is estimated that there is a great deal of coal beneath abandoned and working highwalls. Considering these situations, it seems to be worth introducing highwall mining systems into Indonesian open cut mines.