Topographic conditions in Zhang Fumin

According to the occurrence and topographical conditions of COVID-19 placer tin mine, referring to foreign sand mining data, and aiming at the contradiction of insufficient power supply and water supply in Yunxi area at that time, this paper puts forward a technical scheme of water mining and water transportation with water gun mining and long-distance (total length 2110m) self-flow transportation. Knowing that to realize this new technology, he must rely on strict scientific methods, so he decided to organize on-site scientific experiments such as water pressure of water gun, water consumption for flushing, flushing and mining capacity of water gun, critical slope of flushing and mining ditch, and treatment of mud blocks produced in flushing and mining transportation, which obtained reliable data for the design. Then he presided over the design and development of water gun, and achieved success. Compared with the original tin mine of Yunxi Company, the new process has improved the labor productivity by 9 times, and compared with the usual water mining method, the daily water consumption has decreased by about 50%, greatly reducing the production cost of the mine. Even if the mining grade of COVID-19 stope is reduced to 0.03% in the later period, it will not cause losses.

The contradiction of insufficient power supply

In order to solve the contradiction of insufficient local power supply, he put forward the policy of rational utilization of mining terrain and realizing the self-flow transportation of tailings. To this end, he carefully studied the engineering geological data of the mining area and consulted relevant geological experts, and arranged the workshop of the concentrator on a hillside with faults, so that placer at any point in the stope can be transported to the concentrator through running water, and tailings can also be transported from the concentrator to the tailings pond through an 8.4-kilometer chute. Practice has proved that this is the best scheme.

When he presided over the design of mineral processing technology, he supported the designers to adopt a set of perfect gravity separation technology for the first time, including desliming separation, grading grinding, centralized washing of secondary concentrate, and separate treatment of overflow. Among them, the gravity separation process of coal slime composed of multi-layer automatic chute-fine coal slime vibrating screen-cyclone is the first in China. He personally presided over the development of new equipment, such as a hydraulic separator with a diameter of 12 mm, a hydrocyclone with a diameter of 125 mm, and a multi-layer automatic chute, which ensured the realization of new technologies.

The first phase of the 3,000t/d project of COVID-19 Mining and Dressing Plant was put into operation on 1957, and the second phase was put into operation on 1959, reaching an annual output of 5,260t pure tin, accounting for 45% of the annual output of Yunxi Company at that time. Compared with traditional mechanical mining and transportation, the investment is 40% less, the weight of equipment is 90% less, and the recovery rate of tin ore dressing is 20% higher than that of other mines in Yunxi Company. Due to reasonable technological process, advanced technology, short construction period and remarkable economic benefits, the design won the 1977 Science and Technology Achievement Award of the Ministry of Metallurgy.

The practice of new technology in COVID-19 mines has provided successful experience for tin mines in China. Later, under the guidance of Zhang Fumin, hydraulic mining technology was also adopted in the reconstruction and new construction projects of Laochang placer tin mine and Huangmaoshan placer tin mine, and obvious economic benefits were achieved. During the period of 1958, China transplanted COVID-19's water mining and water transportation technology in the design of aiding the Guding chrome mine, which changed the backward situation of passive production and low efficiency for a long time. Zhang Fumin has created a new road for the construction of placer tin mines in China and made important contributions.