# Quality Evaluation of Wasteless Mining in Dongguashan Based on Intuitionistic Fuzzy Set and VIKOR
## 4 Case Study  
### Overview of the Dongguashan Copper Mine  
The Dongguashan Copper Mine, subordinated to the Tongling Nonferrous Metals Group, is located in Tongling City, Anhui Province. The Dongguashan Copper Mine is now mined to a depth of more than 1200 m. The waste rock of this mine is used for underground backfilling or resourceful sale, and the tailing sand is partially used for underground backfilling. At present, this mine has the characteristics of both modern deep mining and wasteless mining. It insists on scientific mining methods, actively promotes the advanced technology of wasteless mining and is being gradually transformed into a green and ecological modern mine through the recycling of production waste. (1) Waste rock utilization and treatment  
In the design of the mine, wasteless mining with \"no tailing sand in the reservoir and no waste rock discharge from the pit\" is taken as a goal. In the actual production process, most of the waste rock generated during the development period was used to backfill the empty area, and about 300,000 tons of waste rock for infrastructure construction were put up for sale at a temporary dump in the western depression of Lion Mountain. During the production period from January 2005 to June 2010, the Dongguashan Copper Mine produced approximately 4,626,900 tons of waste rock, of which 4,326,900 tons were used for underground backfill and external sale, and another 300,000 tons of waste rock stripped at the initial stage of mining was pending sale. From the infrastructure to the present, the utilization rate of waste rock in Dongguashan Copper Mine is 93.52%. (2) Tailings utilization and treatment  
As for the utilization of tailing sand, the mined-out area is backfilled with the continuous high-concentration backfilling technology of fluidized full tailings in the vertical sand bill. From January 2005 to December 2008, the Dongguashan Copper Mine produced a total of 8,054,700 tons of tailing sand, of which 7,365,700 tons were used for underground backfilling and 689,000 tons were sent to the Shuimuchong tailing pond for storage; during this period, the tailing utilization rate of the Dongguashan Copper Mine reached 91.45%. In 2011, the amount of tailing sand generated from the Dongguashan Copper Mine was 2,533,400 tons. About 1,566,700 tons of tailing sand were used for underground backfilling and the remaining 966,700 tons were sent to the Lao Yaling tailing pond for storage. During this period, the tailing utilization rate was 61.84%. On the whole, the utilization rate of tailings in the Dongguashan Copper Mine was 84.36%. (3) Wastewater utilization and treatment  
Dongguashan Copper Mine has implemented a variety of measures to control water pollution. To protect the water resources, wastewater was treated and discharged by the following methods: (1) the comprehensive treatment and recycling of wastewater in the concentrator; (2) dense backwater treatment of the sulfur concentrate; and (3) comprehensive treatment of return water in a concentrate dewatering station. The pollution discharge of Dongguashan Copper Mine observed the secondary standard in the Comprehensive Wastewater Discharge Standard (GB8978-1996) [25], and the comparison between the discharge standards and the actual situation is shown in Figure 3.  
As shown in Figure 3, the wastewater monitoring value of the total discharge from the sedimentation pond of Dongguashan Copper Mine plant is much smaller than the national standard value, and the wastewater discharge quality here is identified as excellent. To effectively evaluate the quality of wasteless mining, the influence of the effluent on the surrounding surface water and groundwater should be examined.