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Abstract

Gold extraction in primitive artisanal mines usually involves the over-usage of mercury (Hg). This practice results in significant environmental contamination, but is difficult to eliminate due to its effectiveness. Any alternative must be simple, inexpensive and visually effective. This paper proposes a novel, chemical-free method for extracting gold from gravity middlings which has potential as an effective alternative to Hg amalgamation. This method exploits the differences in relative malleability, rather than density, of gold and waste products by submitting concentrates to grinding in a rod mill. The grind products are separated through a sieve, where flattened gold particles are captured on the oversize while brittle waste reports to the fines. Recoveries often exceeded 90%, with nearly pure raw gold separated after only minutes of grinding. While recently adapted to the modern Yukon placer fields, this method has potential to reduce Hg usage by miners in more primitive settings.

Keywords

Mercury alternative Placer gold Artisanal mining Gold processing Comminution Environmentally sustainable Gravity concentration

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References

Clarkson,

1994. The use of nuclear tracers to evaluate the gold recovery efficiency of sluice boxes. CIM Bulletin, 87, (979), pp.29–37.

Clarkson,

G. A.

2015. Extracting gold from gravity concentrates using grinding and sieving (U.T. Dissertations, edn). Masters thesis, University of British Columbia.

Clarkson,

, Clarkson,

and Hitch,

2016. Exploiting the malleability of gold for placer concentrate and recovery. Minerals Engineering, 94, pp.38–40. doi: 10.1016/j.mineng.2016.04.017

Esiler,

and Wiemeyer,

2004. Cyanide hazards to plants and animals from gold mining and related water issues. In: Ware

G. W.

(ed). Reviews of environmental contamination and toxicology. New York: Springer, pp.21–54.

Hilson,

2000. Barriers to implementing cleaner technologies and cleaner production (CP) practices in the mining industry: a case study of the Americas. Minerals Engineering, 13, (7), pp.699–717. doi: 10.1016/S0892-6875(00)00055-8

Hinton,

, Veiga,

and Veiga,

2003. Clean artisanal gold mining: a utopian approach? Journal of Cleaner Production, 11, pp.99–115. doi: 10.1016/S0959-6526(02)00031-8

Osler,

1983. Study of mercury usage in placer mining operations in Yukon Territory and northwestern British Columbia. Prepared for Environment Canada, Environmental Protection Service.

Telmer,

and Stapper,

2012. Reducing mercury use in artisanal and small-scale gold mining: a practical guide. A UNEP global mercury partnership document produced in conjunction with artisanal gold council, 68.

Telmer,

and Veiga,

2009. World emissions of mercury from artisanal and small scale gold mining. In: Mason,

and Pirrone,

(eds). Mercury fate and transport in the global atmosphere. New York: Springer, pp.131–172.

10.

Veiga,

, Ageloci,

, Hitch,

and Velasquez,

2014. Processing centres in artisanal gold mining. Journal of Cleaner Production, 64, pp.535–544. doi: 10.1016/j.jclepro.2013.08.015

11.

Veiga,

, Nunes,

, Klein,

, Shandro,

, Velasquez,

and Sousa,

2009. Mill leaching: a viable substitute for mercury amalgamation in the artisanal gold mining sector? Journal of Cleaner Production, 17, pp.1373–1381. doi: 10.1016/j.jclepro.2009.03.012

12.

Viega,

, Metcalf,

, Baker,

, Klein,

, Davis,

and Bamber,

2006. Crushing and grinding. Manual for training artisanal and small-scale gold miners. Global Mercury Project, pp.16–33.

Reducing mercury usage in artisanal gold mines using grinding and sieving

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