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Don’t let mining waste go to waste

02 December 2022

Supplied by Aspasa

Managing waste is a key component of surface mining and minerals processing operations and should be prioritised to ensure sustainable mining practices are being followed.

This has prompted surface mining industry association, ASPASA, to encourage its members and the broader industry to address the many waste related challenges on our mines. Proper management of waste entails not only a good understanding of the types and quantities but also how it is managed now and in the immediate future.

Monitoring the waste generated over a period will aid in strategic intervention. If you categorise the type of waste, firstly it enables source separation and management more efficiently. Most common waste on mines can be classified as overburden, waste rock, tailings, slags, mine water, water treatment sludge and gaseous waste.

Dust and sludge

Depending on the product being made from scrap stone it generally produces screening residual, wastewater sludge, sawing dust, baghouse fines and stone fragments throughout the process. Additional waste is broken equipment and machinery scrap metal, wastewater sludge, petroleum products, stone waste, kerf waste and general site trash.

The impact of waste is largely measured through quantity, most recently estimated at 175 million tons of quarrying waste annually building up over years implying that action should be taken to reduce and eventually eliminate the major issues caused. Cutting stones, rock, sands and clays produce airborne dust containing very fine particles called respirable crystalline silica (RCS) which could lead to serious health problems and in some cases be fatal.

The waste from quarries and fabrication operations can create dangerous working conditions resulting in health and safety complications for workers and surrounding areas. In the case of wastewater sludge that consists of water contamination issues that pose a threat to our natural waterways, and land nutrients, soil biodiversity with immeasurable impact on the ecosystem.

Reuse and recycle

Best practice guidelines include research for selecting machinery that produces fewer fines, rechargeable energy sources, computer-controlled technology to increase the diversion of waste away from landfills. The desired effect can be achieved through thinking of creative and intuitive ideas of repurposing these materials, finding alternative uses, benefits and value of waste as a resource.

As far as dust is concerned, practicing precaution in the manufacturing process through blade selection, ventilation and wet systems integration is required to establish a safe working environment. Alternative usage in the instance of wastewater sludge after being treated could be disposed of through land spreading, incineration or landfilling. Reselling broken equipment or scrap metal and consider purchasing a stone crusher to resell products for decorative purposes.

Not all scrap stone and fines have uses and should therefore be properly disposed of according to the correct waste disposal procedure. As a result, it needs to be dealt with through innovative thinking and exploring options that may work for individual mines and to take the opportunity to be socially and environmentally responsible and preserve our habitat.

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