The NG Mining Africa Summit will bring together decision makers from across Africa to meet with solution providers who are actively looking to target this exciting growth market.
Metallurgical thickeners have evolved over the past century in large technological leaps rather than through a slow and steady progression. The first of these technological leaps was the introduction of polymer flocculants in the 1950's, which transformed large diameter conventional thickeners. The next leap was the development of more efficient closed feedwells in the 1980's, which better mixed the flocculant and feed more evenly distributed the feed into the thickener body. Lastly, was the development of so called 'auto-diluting' systems in feedwells, approximately 20 years ago, which allowed feed dilution to take place internally. There is still much room for the improvement in thicker design and it is theoretically possible to design smaller, more stable thickeners operating at higher flux rates.
Skorpion Zinc mine is located some 25 km North of Rosh Pinah in South West Namibia. The mine is part of Anglo American’s Base Metals division and complies with the stringent requirements for all health, safety and environmental issues. The primary purpose of this particular project is to clarify the pregnant leach solution (PLS) to enable production of the highest quality zinc metal thereby commanding a premium on the world market.
Hazardous situations can and do present themselves anytime miners or workers are operating around heavy machinery. And even though companies provide rigorous training to keep their employees safe, something simple such as a preoccupation with a job can cause unintentional harm. Proximity detection systems provide warnings to workers should they breech a protected zone, helping to keep them away from these potentially dangerous situations.
By M. Cadwallader, Gundle Lining Systems Inc., USA | M. Cranston, Chemical Waste Management, USA | I.D. Peggs, I-Corp International Inc., USA
By G.R. Koerner and R.M. Koerner, Geosynthetic Research Institute, Drexel University, USA
The use of geosynthetics within the mining industry is not as extensive as within some other industries, such as the hazardous and municipal solid waste industries. However, in certain, very specific applications, the volumes used can be very large, such as in the lining of heap leach pads. This particular application provides two conditions of extreme loading for geosynthetics: extremely large normal loads and severe chemical exposure. The performance of geomembranes in these applications could be useful indicators of likely success in other applications. In applications such as containment of mining waste, where the potential volumes of geosynthetics usage are enormous, application rates remain low. This is attributed to the lack of internationally enforceable legislation requiring the lining of sites storing mining waste. Current areas of application in the mining industry are described in the paper, and suggestions made regarding improvements in awareness and training that could be facilitated by the International Geosynthetics Society. Needs are identified for improved testing techniques and associated performance criteria that are specific to the mining industry, such as heap leach pad liners. Without the confidence provided by such research, it is understandable that mining practitioners are sometimes reluctant to specify the use of geosynthetics in large, critical mining infra-structure projects.
An HDPE geomembrane cap was selected for the closure of a 50 Ha Tailings storage facility in Western Australia. A 1000 year design life for the geomembrane was targeted to meet the stringent environmental and longevity requirement of the project. To maximize the resistance to surface oxidation and the initiation of stress cracking, the material was specified with significantly higher stress cracking resistance, oxidative induction times, oven (thermal) aging resistance, and UV resistance, than the GRI.GM13 standard specification. A comprehensive Manufacturing Quality Assurance (MQA) program of plant audits, material sampling, and laboratory testing was implemented. Stress cracking and oven aging results required some special consideration. A careful investigation, detailed analyses and implementation of stringent MQA program resulted in a material that met the requirements of all parties to the project prior to shipping from North America to Australia.
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