The mineral processor and the environment: Waste to resources.

In the past, we have paid more attention to product than to waste. Unfortunately, the nature of our industry is such that we must extract small amounts of values locked in huge quantities of waste rock.

Today, the mineral processor is collaborating with engineers in the mines, smelters and refineries to generate products of value and treat waste as a secondary resource. The solid wastes and liquid and gaseous effluents can be processed and utilized as value-added products while significantly reducing the harmful discharges. This leads to a sustainable harnessing of our mineral resources in using novel technologies to protect the environment and human health.

I am a great crusader in promoting the environment. I always end my presentations with "we have to go on exploiting the mineral resources of our planet." Therefore, as long as mining continues, for the sake of our own environment the best place to put mine and mill waste products is back where they came from.

Through a process called cold-bond tailings agglomeration (CBTA), several types of wastes have been physically and chemically altered into a less reactive and more easily-handled state. With the addition of a small percentage of cementing binder, mill tailings have been successfully agglomerated into pellets which are considerably less reactive than in their original state.

In addition, steel and iron mill sludges which have become a large waste disposal problem in the steel industry, have been successfully agglomerated through a process of pressure agglomeration.

Agglomerated mill tailings can also be used underground in mines for ground support as paste fill.

This agglomerated tailings paste fill (ATPF) consists of pelletized mill tailings as aggregates and also tailings for the matrix of paste fill along with cementing binders. This ATPF results in minimal tailings disposed of in tailings ponds, thereby reducing the potential of acid mine drainage.

In addition to the environmental benefits, it has been shown that the strength characteristics of ATPF, which is exclusively made of tailings, is comparable to currently used paste fill which often supplement mill tailings with alluvial sands and waste rock to boost its strength.

Further research has been conducted to lower the costs of ATPF by utilizing other inexpensive cementing binders such as fly ash, gypsum, blast furnace slage and lime.

Work is continuing on further developing ATPF and utilizing this technology in underground mines.

Lucky Amaratunga's presentation topics include: Sources of Wastes; Disposal Options; Recycling of Automobile and Electronic Scrap Using Mineral Processing Techniques; Environmental Industry Boom in the Future; The Role of the Mineral Processor in the SO2 Abatement Program in the Minerals Industry; the Application of Mineral Processing Techniques in Other Industries; Tailings to Resources (two major Canadian examples); Environmental Backfill Research at Laurentian University (Amartunga's own research and specific field of expertise)