Development of High Intensity and Low Loss mining Technology
For the technology improvement, certain thrust areas have been identified, viz. increase in mining intensity, reduction of ore loss and mineral dilution including increase in extraction rate, especially from underground mines.
In China, earlier mining with gentle slope was in practice. Working slope was 8 – 15o in general. Therefore, removal of waste was high in pre-production stage and construction period was also high. Thus, to have achieved full production, it used to take a long time. In 1980s, experiment on steep slope mining had been made successfully in certain mines and now slope angles of 20 – 30o are achieved in working opencast iron ore mines. Stripping ratio during production period was decreased by 20 percent and also has the flexibility as to performing the exposure of final pit walls by 3 – 9 years. In Nanfen Iron Ore Mines, truck haulage has been introduced replacing the inflexible rail haulage which was predominant haulage system in China till the recent past.
According to the feasibility report of this mine, which has been implemented now, stripping ratio during production has decreased from 3.4 to 4.8/t. Now, yearly development and stripping during the early period can be reduced by 15 Mt rock. Some 180 Mt rock stripping can be postponed during the full period. So the steep slope mining has brought in increased high wall and its steep angle of slope. There are a few mines having 13 to 15m bench height which are now being increased to 15 – 17 m. Stability of these benches is being maintained by multiple row millisecond delay blasting technique. Such mining intensity and positive effects on economy of opencast iron ore mining have been experienced in China in recent years.
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Development of High Intensity and Low Loss Mining Technology
Development of High Intensity and Low Loss mining Technology
For the technology improvement, certain thrust areas have been identified, viz. increase in mining intensity, reduction of ore loss and mineral dilution including increase in extraction rate, especially from underground mines.
In China, earlier mining with gentle slope was in practice. Working slope was 8 – 15o in general. Therefore, removal of waste was high in pre-production stage and construction period was also high. Thus, to have achieved full production, it used to take a long time. In 1980s, experiment on steep slope mining had been made successfully in certain mines and now slope angles of 20 – 30o are achieved in working opencast iron ore mines. Stripping ratio during production period was decreased by 20 percent and also has the flexibility as to performing the exposure of final pit walls by 3 – 9 years. In Nanfen Iron Ore Mines, truck haulage has been introduced replacing the inflexible rail haulage which was predominant haulage system in China till the recent past.
According to the feasibility report of this mine, which has been implemented now, stripping ratio during production has decreased from 3.4 to 4.8/t. Now, yearly development and stripping during the early period can be reduced by 15 Mt rock. Some 180 Mt rock stripping can be postponed during the full period. So the steep slope mining has brought in increased high wall and its steep angle of slope. There are a few mines having 13 to 15m bench height which are now being increased to 15 – 17 m. Stability of these benches is being maintained by multiple row millisecond delay blasting technique. Such mining intensity and positive effects on economy of opencast iron ore mining have been experienced in China in recent years.