MANILA, Philippines – A geology expert said banning open pit mining method has dire implications in construction, cement manufacturing and other key industries.
“People opposed to open pit mining do not know what they are saying. The open pit mining method is surface mining. It means entry and exit of materials all begins from the surface as compared to underground mining where at some point in time one operates below the surface,” explained Dr. Carlo A. Arcilla, director of the National Institute of Geological Sciences (NIGS) at the University of the Philippines (UP) Diliman.
“People may not know that a simple example of open pit is quarrying.”
He added that if quarrying isn’t allowed, there wouldn’t be construction activities. “Where will we get all the aggregates like stones, sand, and cement that come from limestones? Maybe what they [anti-mining groups] want to say is ban open pit mining for metals.”
Countries that have advanced industries use open pit mining methods to extract minerals from the soil.
Dr. Arcilla said Canada mines its coal using the open pit mining method. Coal is Canada’s main source of power. “And it is ‘mine to mouth method’ – coming from the mine the coal goes directly to the power plant. It’s the same thing in Australia where most of their exported ores and iron are mined using the open pit method.”
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Arcilla said among the companies in the Philippines that employ the open pit mining method are Semirara, PhilMinera, Oceana Gold, Atlas mining in Toledo, Cebu, and the thousands of quarries including cement firms Holcim and Lafarge that mine limestone by open pit.
“A lot of these (in open pit mining) are respectable companies,” according to Arcilla.
Open-pit mines are dug on benches that are usually on four meter to 60 meter intervals. The steps on the walls help prevent rock falls continuing down the entire face of the wall.
A haul road is built on the side of the pit, forming a ramp up for trucks to carry ore and waste rocks that are piled up at the waste dump located at the surface near the edge. To minimize degredation, the waste dump is also tiered and stepped.
Processed ore, which is known as tailings, is pumped to a tailings dam or settling pond, where the water evaporates.
By law, there should be a mining rehabilitation plan. After mining finishes, the mine area must undergo rehabilitation.
“I understand the concern of anti-mining groups is that the wastes should not leak. In the case of the proposed Tampakan Gold Copper Project (TGCP), it is important to look into the good reputation of Sagittarius Mines, Inc. and Glencor-Xstrata,’ Arcilla said.
Arcilla, who is also an affiliate graduate faculty at University of Hawaii’s School of Ocean, Earth Science and Technology, said what will happen in the Tampakan Project in South Cotabato is a huge open pit.
He had studied the rocks in Tampakan and the mineral deposits are close to the surface. “Below Tampakan are agriculture-based communities and I would understand the opposition of anti-mining groups but let us be aware that SMI is a reputable company.”
“With the price of copper now at 3.5 to 4 dollars per pound, SMI will be milling more or less 1,000 tons per day.”