In the period of 1960 – 1972 exploration for iron sand deposit had been done by PT. Aneka Tambang particularly along the southern coast of Cilacap Regency, East Java Province; and was successfully identified a total iron ore reserve of 2,655, 236 tons with an average grade of 51.7% Fe within the mining concession area of 3090.43 Ha. The reserve was classified into 2 (two) categories such as indicated and measured with respectively sum of 724,511 tons and 1,930,725 tons. In August 1970 the reserve was initially exploited; and then during the period of 1971 – 1978, the company produced a total of 300.000 ton iron concentrate/year to fulfil the need of exporting target to Japan. Beginning in 1979, the iron concentrates were produced for domestic marketing with priority to supply cement industry.
Since October 1st-2003, mining operation was legally terminated; and currently is in the process of closing decision handled by the Centre of Mineral and Coal Reasearch and Technology – Department of Energy and Mineral Resources. Meanwhile the company was apparently still producing iron concentrate (originated from Kutoarjo mining concession, Central Java) in the frame of supply fulfilment to domestic cement factories. During the period of 1971 – 2003, the company had produced a total iron concentrate of 6,677,015 tons with marketing/saling rate reached a total of 3,972,242.28 tons. Evaluation result exhibits that conservation programme wasn’t involved within mining activity, but there were monitored some indications of conservation application such as : efforts to determine accuracy of the reserve, resources enhancement to become reserve, optimalizing exploitation and examination of ore for precise utility.
Exploitation of claystone and limestone deposits done by PT. Semen Nusantara was aimed to comply the need of supplying raw material for cement industry. The total reserve of claystone was 50,000,000 tons within an area of 250 Ha, whilst limestone reserve’s totally 413,570,812.50 tons within an area of 1.000 Ha. The company’s planning to produce 4,100,000 tons cement/year with consequency to provide raw materials of 1,333,517 tons claystone and 5,330,918 tons limestone/year. There’s evaluated that the company had tried to practise some parts of conservation application within mining sistem, such as : resource treatment to become reserve, enhancing mining/processing recovery and quality of cement product.
