Solving ‘green’ challenges in remote diamond mines
Adoption of the DSI Sandwich belt high angle conveyors minimizes environmental impacts
Twenty-five years ago, “going green” wasn’t quite the popular phrase that is it today. However, in the late 1990s, Dos Santos International was presented with a “green” challenge to use the least amount of space possible to process and separate one of the Earth’s greatest treasures – diamonds – at De Beers’ Snap Lake underground mine in the Northwest Territories.
Because of Snap Lake’s remote location, construction and operations required careful planning. This led to the development of the space-saving DSI Sandwich Belt high angle conveyor technology – an invention of DSI president, Joe Dos Santos.
Being located in a hostile, Arctic environment, the kimberlite processing facilities had to be enclosed and heated. A smaller footprint for the plant was determined to be the optimal way to minimize environmental impact and cost.
In the process building, the kimberlite had to be elevated then discharged into the various crushing, screening and sorting functions. The original concept was to use a multitude of Sandwich conveyors to minimize the facilities. This was ultimately rationalized to require only two Sandwich conveyors, which defined the facility’s minimal footprint. The ability to convey at any high angle made the DSI Sandwich Belt high angle conveyors ideal. The Sandwich belt technology imparts a gentle, yet firm hugging pressure on the material in the belt sandwich. This allowed the precious gems within the kimberlite to be elevated at high angles without damage or spillage. The Snap Lake project incorporated two DSI Sandwich conveyors, each travelling to opposite ends of the building. The units were standardized at 36” belt width to simplify spare parts inventory. Design of the units included provision for future upgrade, from 275 t/h to 524 t/h, merely by increasing the belt speed. By operating at the lower speed until the upgrade was required by the Sandwich conveyors, optimal energy efficiency was preserved. In addition, for heated facilities in cold climates, Sandwich coneyors offer the least heat escape, and thus the lowest heating costs.
Snap Lake operated to very high environmental standards and certified its environmental management systems to international standard ISO 14001.
The success of Snap Lake led to the incorporation of three DSI Sandwich Belt conveyors into the Victor mine, the first diamond mine in Ontario. Inventory at Victor was simplified with all units at a 42” belt width. However, tonnage requirements for these units varied from a low of 185 t/h to a high of 422 t/h. For prolonged equipment life and energy conservation, one unit (11) ran at a slower speed.
Other industries have also used Sandwich Belt conveyors. Because their profiles can conform to irregular (steep) paths, they are able to blend in with the surrounding environment. This feature also precludes the need for many transfer points, a common source of spillage and fugitive dust. By virtue of their high capacity, high angle and adaptable profile features, Sandwich conveyors facilitate the most compact arrangement of any materials handling system. This of course minimizes disturbances of the environment, and results in a most economical system when all aspects (including the value of real estate, cost of site preparation and excavation) are considered.
This article was provided by Dos Santos International (www.dossantosintl.com)
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