On November 6, 2019, we received gold samples from customers in Chennai, India, with a total amount of about 60kg. Sample and mix evenly, dry and test, and the moisture is about 18%. The grade of raw ore Au is about 0.6g/t, and the fineness of ore sample is fine – 200 mesh, accounting for 87%. The purpose of the experiment is to conduct a detailed beneficiation feasibility test on this high gold tailings to judge whether it has production value. A large number of cyanide leaching tests are required.
Finally, the following indicators are achieved:
The effect of conventional cyanide stirring leaching is very good. When the leaching time is 24h, the grade of cyanide residue is 0.1g/t, and the cyanide recovery of gold is 83.33%, that is to say, 0.5g gold can be collected per ton from the tailings, which has considerable benefits.
Why choose pit leaching?
When heap leaching is not convenient for beneficiation in small-scale gold mines, pool infiltration transition is frequently used for beneficiation. However, the leaching rate is 50-70% lower with the traditional pool leaching method. Under the action of aqueous solution in the pool, the clay ore gradually hardens, most of the pores formed during charging disappear, the water permeability is greatly reduced, and the leaching is not complete. A large amount of clay in the ore can even prevent the pool from leaching. It involves mixing a small amount of infiltration material into the ore, putting it into the tank, and spraying the liquor leaching solution evenly to prevent hardening of the ore in the tank, which improves permeability and leaching rate. To verify the feasibility of this process, several column leaching tests were performed with the traditional process and with this process. The diffusion rate of the latter was up to 94%, compared to 60% for the former. The leaching conditions of forward leaching test are similar to those of pit overflow production.
There is no risk in using this process,
Small nozzles such as crusher and nozzle need to be added.
Cost and profit assessment
There are only a few pieces of small equipment needed for this process, even without adding any. Material costs are only raised by 0.50 yuan per ore, due to the improvement of leaching rate. By improving the leaching rate, slag grade can be reduced by 0.2-0.5g/t. By treating at least 50000 tons of ore per year in a small pool leaching plant, at least 10 kilograms of gold can be produced annually.