Produced by Oxus International with the help of EcoSafety, and the Biotechnology Institute of the National Academy of Sciences of the Kyrgyz Republic

Transcription

1 Produced by Oxus International with the help of EcoSafety, and the Biotechnology Institute of the National Academy of Sciences of the Kyrgyz Republic The Biotechnology Institute of the National Academy of Sciences of the Kyrgyz Republic

2 This presentation provides information on cyanide, and how it is used by environmentally responsible gold mining companies in close proximity to communities. It also aims to dispel myths about cyanide s environmental impacts and health risks. The research has been produced by a Kyrgyzstan-based research company, Oxus International, working with the NGO EcoSafety and the Biotechnology Institute of the National Academy of Sciences of the Kyrgyz Republic. It has been funded by the mining company Manas Resources, who exercised no editorial control over the findings of the research or the construction of this slideshow.

3 Cyanide is a chemical that is produced from both natural and industrial sources. Cyanide exists in small amounts in nature, such as in almonds, apples and sweet potatoes.

4 Cyanide in mining only accounts for 18% of its total usage. Cyanide is mainly used for industrial purposes in pharmaceuticals and plastics, but also has medicinal and artistic uses. 18% Mining Other Industries 82%

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6 Exploration Geologists study an area to gain more specific knowledge of the geology and mineral composition and decide where and how to proceed with mining operations. Drilling rig in Crescent Valley Nevada, USA Threedimensional model of geology at Kubi mine, Ghana

7 Construction and Mining The mine, leach heap, processing plant and other facilities are constructed. Blasting and heavy machinery are used to expose and loosen layers of rock. Rocks that contain sufficient valuable metals are called ore. Heap leach pad at Elansdrift mine, South Africa Blasting at Silver Bell mine, Arizona, USA

8 Loading and Crushing The ore that result from blasting and mining are collected, crushed into finer pieces, and transported to the leach heap. A rock crushing machine in Australia A pile of crushed rock in South Dakota, USA

9 Heap Leaching Process Crushed ore is stacked on a lined artificial or natural pad or in large containment (vats) and is sprayed or dripped with a low concentration of cyanide solution. Gold is recovered into the solution. The cyanide solution is carefully prepared to ensure its chemical stability. Cyanide solution soaks the ore below at the Mesquite mine in Nevada, USA Construction of the leach pad at Kişladağ mine in Turkey

10 Extraction and Smelting The gold bearing cyanide solution is pumped into columns filled with activated carbon and gold is absorbed from the solution onto carbon. The gold loaded carbon is transfers to a stripping circuit where gold is recovered from the carbon and precipitated as a solid by electrolysis. The gold from the electrowinning circuit is smelted to remove impurities such as iron to produce Dore bars that contain 70-95% of gold. The leached ore is washed with process water to remove traces of cyanide prior to rehabilitation. The wash solution returns to the process. Gold bars in various sizes Processing plant at Kalgoorlie, Australia

11 Water Recycling There will be no discharge of industrial wastewater, domestic sewage or storm runoff from the process plant area to sensitive water bodies or onto the ground surface All wastewater will be treated in accordance with sanitary or industrial standards and return to the heap leaching process.

12 Rehabilitation and Closure Most mining companies determine an appropriate closing scheme before mining operations begin. This step ensures that the environment is protected and returns to its pre-mine state as closely as possible. Golden Cross Mine before rehabilitation, New Zealand The same mine following rehabilitation

13 Gold extraction from low-concentration ore deposits by cyanide heap leaching is the most economically viable method characterized by low economic risks and minimum impacts on the environment. It is used in 80% of all gold mines in the world. Due to heavy regulations and safety procedures, there have been only 8 major cyanide spills recorded since 1992 worldwide.

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15 There are about 460 gold mines around the world that use cyanide. Since 1992, there have been only 8 major cyanide incidents. The International Cyanide Management Code was created in 2000 to improve the management of cyanide in the mining industry and help prevent major incidents.

16 If used improperly, cyanide can be dangerous to humans, birds, fish and other wildlife. Humans can experience breathing and nerve issues if exposed to toxic levels of cyanide. Research shows cyanide does not accumulate in the body or environment. It does not cause cancer or birth defects in humans.

17 Cyanide is quickly broken down by sunlight and other natural processes that transform it into harmless compounds.

18 In May 1998, a truck accident caused the loss of about 1,800 kg of sodium cyanide into the Barskoon River. Despite media reports, the long-term effects of the spill were negligible. Levels of cyanide in the air and soil never reached dangerous amounts in populated areas. After two weeks, the cyanide had dissipated to 1/1000 th of its peak levels.

19 Many large gold mines that use cyanide run successful operations in close proximity to residential populations all over the world. Examples include: Super Pit in Kalgoorlie, Australia. Population: 32,390 Martha Mine in Waihi, New Zealand. Population: 4,503 Morro do Ouro in Paracatu, Brazil. Population: 81,599

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23 The gold mining industry is very heavily scrutinized, causing constant improvements in safety and environmental practices. Because of the attention that many mining companies receive, it is in their best interest to minimize environmental impacts and to mine safely. Many of the world s largest gold mines are in North America and Australia where there are very strict cyanide regulations. These companies use cyanide responsibly for gold extraction, even in close proximity to local communities.

24 Mining companies can minimize pollution, dust, noise, and changes in landscape by installing water or air emission treatment facilities, regularly testing air and water for pollutants, implementing waterspraying systems and planting natural vegetation barriers.

25 Blasting is a required part of many gold mining processes in order to loosen the rock which contains gold. The main impact of blasting is the potential for disruptive levels of noise and vibration in nearby communities. Blasting can also have negative impacts on animals in nearby communities.

26 Mining companies undertake extensive studies to develop blasting designs that mitigate negative impacts on communities and animals as much as possible. The blasting process is as follows: Informing the community of blast times; Drilling holes in the ground according to the blast design; Inserting blast charges into the bores; Detonating the charges sequentially with minimal duration to mitigate effects of vibration and noise; Monitoring and recording blasting data to ensure stringent safety and environmental standards are met.

27 Mining operations create direct and indirect employment opportunities for nearby communities. Many mining companies seek to hire as many local workers as they can and use local suppliers for mining needs. In addition, many mining companies provide vocational training to local workers to help them find jobs elsewhere after mine operations finish.

28 Many mining companies implement development initiatives in the local communities such as road upgrades, school improvements, and long-term income generating projects (vegetable gardens, vineyards, tourism projects).