Yunnan Copper Group: Whole process management for a green mining model

Company profile
 
Yunnan Cooper Cooperation Limited (hereinafter shortened as Yunnan Copper Group) is a large enterprise group approved by the people's government of Yunnan province and the former China Nonferrous Metal General Corporation in 1996, consisting of Yunnan Smeletry, Dongchuan Copper Mines Administration, Yimen Mining Bureau, Dayao Copper Mine and Mouding Copper Mine. While focusing its business on copper prospection, exploration, beneficiation, smelting and processing, it also deals with taping of zinc, titanium, molybdenum, and phosphorus resources, and comprehensive recovery of rare and precious metals including gold, silver, platinum and palladium. Its scope of business also covers geological prospecting, engineering consultation, chemical production, futures trading, logistics and transportation and international trade. Yunnan Copper Group now has established companies in provinces like Yunnan, Sichuan, Inner Mongolia, Xinjiang, Qinghai, Tibet and Guangdong and in countries like Zambia, Australia and Laos, owning 94 wholly-owned or share-controlled companies.
 
Challenges
 
The development of the mining industry has satisfied our demand for energy and made great contributions to enhancing the national economic strength, promoting social development and improving people's living standards. However, due to some small mines backward mining technology, extensive mining methods and inadequate management methods, large waste of resources and environmental pollution has been caused. With the continuous improvement of living standards and production techniques, people have put forward higher requirements on mining efficiency and mining methods. How to form a green mining mode that balances both the economy and the environment has become an important research topic in the development of mines.
 
The Pulang copper deposit is now the biggest porphyry copper mine in Asia. As a super-large mineral deposit, it is also the biggest resource project invested by Yunnan Copper Group in recent years. The deposit is close to the world natural heritage site, the Three Parallel Rivers of Yunnan Protected Areas, and the national scenic spot, the Potatso National Park. As a result, the ecological environmental protection requirements for the whole process of copper mining are stricter and the standards are higher. A greener and more efficient mining mode must be found.
 
Solutions
 
During the process of mining, Yunnan Copper Group paid great attention to biodiversity protection, adopted an advanced environmental mining mode, and disposed mining wastes timely, aiming to build a model of green mining.
 
Conserving biodiversity
 
During the prospecting period, the company entrusted a professional institute to conduct field investigations on areas in and surrounding the site of the first period mining and selecting engineering construction of Pulang copper deposit, including the mining area, opencast mining site, underground mining field, barren rock yard, mineral processing site, tailings pond, tailing pipelines, water sources, waterlines, office buildings, living area and explosive store, so as to clarify influences of mining activities on biodiversity and to make the Influence Evaluation of Pulang Copper Deposit on Biodiversity. Built on the evaluation results and suggestions, the company optimized its project engineering design to reduce influences of mining activities on biodiversity to the greatest extent. After the project was under construction, the company took timely actions to restore and govern ecological environment based on its surroundings and characteristics of the area. It implemented the green project of trees and grass plantation and slope management to improve the greening rate of the mining area.
 
Implementing green mining
 
Adhering to the principle of minimizing its damage to ecology, Pulang copper deposit replaced opencast working with underground natural caving. All the mining work is done under the mine. By way of undercutting at the bottom of the ore body or a certain ore section, rocks of the upper part collapse steadily and continuously under the forces of their own gravity and stress, without relying on the forces of blasting.
 
In order to improve the safety of mining, the deposit adopted intelligent devices and control technologies, including the online intelligent monitoring system for the whole process of mining and selecting, the unmanned transportation system, the unmanned scraper system, the intelligent unmanned operation system for the whole process of beneficiation and the long-distance intelligent tailings transportation monitoring system, thus building a whole-process intelligent production line covering prospecting, mining, processing, production and management.
 
During the process of mining, the deposit also involved a third-party company with qualifications on environmental supervision and water and soil conservation supervision into the construction, supervision and management of the project, with an aim to provide professional technical support and supervision and management guarantee for green mining.
 
Reducing emissions of wastes
 
In order to minimize environment contamination risks aroused by tailings leakage and permeation, the deposit laid HDPE anti-osmosis membrane of high anti-corrosive performance, high imperviousness and high tensile strength on the bottom of the whole tailings pond, which effectively insulated the contamination of tailings sewage to soil and underground water. The company built 3 temporary under-mine water burst treatment stations, 2 temporary domestic sewage treatment stations and 1 permanent domestic sewage treatment station to deal with production and domestic sewage.
 
After discharged from the beneficiation plant, the produced sewage (tailings slurry) is drained to the tailings pond after being concentrated by high-efficient concentrators. Then, the clarified slurry is drained to the beneficiation plant for reuse by booster pump, thus achieving zero emission. The domestic sewage being treated by sewage treatment plant and reaching the emission standard is used to irrigate vegetation in the mining area so as to make full use of resources and to reduce sewage discharge.
 
The comprehensive utilization of barren rocks (rock containing no copper) produced during the mining was also carried out. The company built a barren rock processing plant near the barren rock yard to process barren rocks produced and to use them as construction material, which not only reduced the stockpiling of barren rock, but also avoided new destruction caused by excavation of sand and stone for construction use.
 
Achievements
 
Social benefit
 
Compared with the traditional opencast mining, the mining work amount and unit explosive consumption of underground natural caving method were significantly reduced, which greatly reduced the influence of mining on the ecological system of the mining area. The volume of the barren rock produced using natural caving method was around 1.01 million tons, reduced by 186.07 million tons compared with that of opencast mining, decreasing by 99.46%. Meanwhile, with the reduce of explosive consumption, the unit emission of waste gases like carbon oxide and nitric oxide was also reduced.
 
The all anti-osmosis treatment of tailings pond reduced the environment contamination risks caused by tailings leakage and permeation to the lowest. Sewage treatment stations were built during the construction of the mine. In total, 6.416 million cubic meters of sewage was treated since their establishment. All the water discharged to the surface runoff has reached the water discharge standard of national II, thus reducing the influence of mining activities on the quality of surrounding rivers to the greatest extent.
 
The comprehensive utilization of barren rock reduced the stockpiling of barren rock and avoided its damages to the environment caused by rain wash. Pulang copper deposit adopted the green environmental protection concept through the whole process of mining and promoted the building of green mining and its harmonious development with ecological environment actively. It has set up a good enterprise image and is highly praised by all sectors of society.
 
The company adopted an automatic production line, which effectively improved labor productivity. The production efficiency of mining and processing process has reached international leading level and domestic first-class level. The mining cost was lowered by 23%. Compared with traditional mining of the same scale, the number of employees has fallen sharply, reducing from 3000 to 697. It not only reduced the labor cost but also lowered the incidence of accidents, thus improving the safety of mining work.
 
Barren rock processing plant processes barren rocks and turns them into high-end construction materials, which creates huge economic value. In 2016, the barren rock processing plant produced 200,000 cubic meters of sand and stone material, creating a revenue of 12 million yuan.
 
Prospect
 
Pulang copper deposit is the newly developed major copper mining project of Yunnan Copper Group in recent years and is a successful example of the transformation from traditional mining development to green mining development. In the future, Yunnan Copper Group will actively advocate the mining development concept of “both invaluable assets and lucid water and lush mountains”. Through technological progress and scientific management, this young mine will be built into an advanced technology, environment-friendly project with fruitful results and a benchmarking of the harmony of business and nature promoted by China’s copper mining enterprises, providing a positive role of demonstration for more mining projects at home and abroad.