Currently, Vietnam National Coal and Mineral Industries Group (TKV) is continuing to direct coal production and screening units to do a good job of recovering rock and coal, arranging suitable dumping areas; at the same time, actively seeking new directions to propose to the province on the plan to sell mine waste rock outside the province. If this policy is implemented, a large amount of mine waste rock will be transported and sold outside the province, which means that TKV will save a lot of costs related to the current treatment and dumping work.
Deo Nai Coal Joint Stock Company is a large-scale open-pit coal mining unit of TKV, with an average annual output of over 2.5 million tons of raw coal. "According to the technological process, to exploit the above coal output, each year, Deo Nai Coal will have to excavate and dump 19-21 million m3 of waste. soil and rock, stripping coefficient of over 13m3 /ton. Not to mention 300-500 tons of waste rock each year from screening and coal recovery activities from non-coal products. This leads to pressures on the scale of the dumping site, transportation costs, labor costs, environmental costs..." - Mr. Nguyen Ngoc Tung, Deputy Director of the Company said.
Not only Deo Nai Coal, the volume of excavated and dumped soil and rock of coal industry units is getting larger and larger, due to the increasingly deep mining area. Most open-pit mines have approached the mining depth of -200 to -300m compared to sea level. Preliminary calculations show that to mine one ton of coal, it is necessary to excavate 11-13 million m3 . Soil and rock. Thus, on average, each year, the amount of excavated soil and rock waste from the mining technology of TKV's open-pit coal mines is about 150 million m3 .
Screening and consumption units also discharge a huge amount of processed stone and also have to bear the pressure of dumping area and many related costs.
Cua Ong Coal Selection Company - the unit operating the largest coal screening and processing line system in the Group, on average, Cua Ong Coal Selection Company operates production with about 12-13 million tons of raw coal screened and processed each year and the amount of waste rock is up to more than 1.3 million tons. According to regulations, this type of waste rock is no longer usable and must be dumped into the planned waste dumps of the coal industry.
To handle this large volume of waste rock, Cua Ong Coal Selection Company has arranged a Transport workshop with modern and synchronous human resources and equipment. And the Transport workshop is currently managing 38 locomotives of all kinds, over 640 wagons of all kinds and more than 500 employees operating 3 shifts/day. In addition, the Company is still managing and operating a waste rock transport system back into the mine, with a total transport volume from 2020 to present of more than 3 million tons of waste rock.
According to Mr. Nguyen Quang Hung, Deputy Director of the Company, currently, the transportation cost/ton of waste rock from the screening plant to the Dong Cao Son mine dump is about 60,000 VND/ton. Along with many related costs such as leveling, renting transportation roads, each year, the enterprise spends from 75-80 billion VND to "take the trash to the dump".
More than 1 billion m3 The amount of mine waste rock from production, screening, processing and consumption units currently stored at TKV's waste dumps has been a concern for many generations of leaders of the coal industry and Quang Ninh province. Previously, this amount of rock was only used to fill mining pits, renovate waste layers, and restore the environment of coal industry units. However, the amount of mine waste rock processed in this way is still too small compared to the amount of waste rock currently stored at the dumps.
In 2017, a local enterprise received approval from the province and TKV to use mine waste rock at Dong Cao Son dump to produce artificial crushed sand, replacing natural sand. This is also the first time a sand and stone processing line has been brought to Vietnam and placed at a large dump in the Cam Pha coal region - where every year about 32-36 million tons of rock and soil from mines are discharged and a lot of money is spent on waste treatment.
Continuing to implement the circular economic development strategy according to the policy of Quang Ninh province, since 2018, TKV has calculated the possibility of reusing mine waste rock and soil as filling materials for industrial and civil construction works in the area. After many efforts of the province and TKV, at the end of 2022, the Group started exploiting and recovering mine waste rock and soil to serve the filling of civil and industrial works in the area of the Southern Pillar Waste Dump - Suoi Lai Mine, Hon Gai Coal Company - TKV, with a recovered volume of 3.5 million m3 .
However, the volume of mine waste treated in this way is still limited, while every year, the Group's mining, screening and processing lines are still discharging hundreds of millions of m3. soil and rock
Currently, in Quang Ninh province, only a few enterprises have agreed to buy waste rock from TKV as raw materials for the production of construction materials. To continue to find new directions for mine waste rock in Quang Ninh, TKV actively proposes and requests permission to sell mine waste rock outside the province to enterprises that need to use it as filling materials and construction materials. If this policy is soon approved, TKV will greatly reduce the burden of costs, while increasing its revenue.
However, the relevant departments and TKV will need to make strict commitments to ensure the processing, transportation and properties of mine waste rock when selling to businesses outside the province in need, avoiding risks of resource loss and loss of security and order during the implementation process.
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