1 Introduction
Boss Hill is part of the Noranda Mining Company. Located in the British Columbia-Columbia province, north-north of Vancouver. The factory is 1500m above sea level. Molybdenite was discovered in 1917. Exploration work was completed in 1965. In 1966, the 900t/d molybdenum plant was put into operation.
The existing mining capacity is 3,300t/d. According to the recoverable molybdenum resources calculated at the end of 1983, there is still 6 years of mining potential.
2. Deposits, ores and mining
The Bosishan molybdenum deposit is a porphyry molybdenum deposit, and the vein is distributed in the granitic- diazoite . A portion of a trough consisting of a number of breccia tubular bodies, about 330 m deep, 60-120 m long and 9-30 m wide, surrounded by molybdenum-rich quartz veins in the upper breccia.
There are three forms of molybdenum ore production: (1) The quartz veins of the breccia veins are mineralized in the form of fine-grained disseminated. (2) The coarse veins or fine grained mineralized layers in the quartz veins. (3) Along the cracks, joints and shear planes, it is a thin layer of fine particles.
Molybdenite ore, in addition, the metal as well as mineral pyrite ore brass and a very small amount. Molybdenite has a simple symbiotic relationship with other minerals and is easily dissociated from the monomer during grinding. Associated rocks are volcanic rocks - tunnel rocks and fine rocks.
According to the statistics of the end of 1983, the ore reserves are 4Mt, the recoverable molybdenum metal is 4kt, and the original ore molybdenum grade is 0.141%.
The Boss Mountain uses the mining scheme of the open pit mining, with an open pit mining capacity of 1466 t/d and a pit mining capacity of 1832 t/d.
3. Process selection process
The dressing process is shown in the figure below.
Tubosshan beneficiation process
(1) Crushing process: three sections and one closed circuit. The maximum feed is 600mm, and the final crushed product has a particle size of 80%-10mm.
Coarse crushing equipment: 1 set of 915×1220 jaw crusher . The discharge port is 32mm. The maximum breaking capacity is 163t/h·table.
The medium crushing adopts a 1296mm standard cone crusher , and the discharge port is 14mm. The fine crushing machine adopts a 1678mm short-head cone crusher , and the discharge port is 8mm. The comprehensive crushing capacity of the medium-fine crushing system is 118t/h. [next]
(2) Rough grinding-rough selection process: one section of ball mill and cyclone closed circuit, one rough selection and one sweep selection.
(3) Rough grinding equipment: 1 set of ¢ 3.4 × 4.6 m ball mill . Its maximum processing capacity is 83t / h · Taiwan. The ball mill has a rotation speed of 18 r/min and a rotation rate of 76%. The ball mill electromechanical consumption is 14kW·h/t, the ball consumption is 0.67kg/t (using nickel- iron cast balls), and the additional steel ball diameter is l00mm (73%) and 75mm (27%). Closed with the ball mill are two D20B Krebs cyclones with a sediment concentration of 74% and a fine flow of 50%-200 mesh.
(4) The coarse and sweeping selection uses 44 tanks of the Akitel 48 flotation machine.
Selected Process: Unlike the above several plants, the Boss Mountain Collection is a small selection plant that uses a re-grinding and ten-selected process. Similar to many molybdenum plants in China. The difference is that there is no fine sweeping, and the selected tailings are not directly returned to the roughing operation. Instead, the grading is first carried out, the overflow is returned to the rough selection, the grit is returned to the coarse grinding, and the refining is carried out by the medium ore (rough grinding and medium). After the mine re-runs a billiard mill, it enters the rough selection. The concentrate is re-grinded with a 1220×2440mm Denver ball mill with a speed of 27r/min and a transfer rate of 70%. The ball size is ¢38mm cast steel ball. The regrind mill is closed with a ¢50mm cyclone, and the overflow fineness is 76.6%-352 mesh.
Selected operating agents and consumption: 6 times, 10 times of selection and re-grinding, adding sodium silicate; 1, 3 times of selection and re-grinding, adding sodium cyanide, each selection is added pine oil.
Medicament (consumption g/t in 1976) | |||
lime | 350 | Coal oil | 86 |
Pine oil | 30 | Sodium cyanide | 33 |
Sodium silicate | 97 | ||
Boss Mountain 1976 production indicators:
The ore grade is 0.21% Mo; the concentrate grade is 55.45% Mo;
The tailings grade is 0.027% Mo; the recovery rate is 87.21%; the water + oil is 5%~7%.
Cost (per ton of raw ore) (Canadian/tonne ore):
Mine 4.44; factory 2.15; maintenance 0.70;
Management 2.02; total 9.31.
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