Engineering & Mining Journal

APR 2019

Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr

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WASTE MANAGEMENT APRIL 2019 • E&MJ 35 www.e-mj.com mining — recovery of valuable metals from e-waste — and also have the potential benefit of positioning mining as an active player in seeking solutions to some envi- ronmental problems that its critics blame it for: e.g., digging up metal-bearing ores in remote and often environmentally sen- sitive sites, only to have those metals, once made into salvageable components, eventually buried again in landfills. There's also a financial aspect. Recent studies indicate that recovery of copper and gold from recycled CRT tubes, for in- stance, costs 13 times less than extracting the same amount of metal from virgin ores. An organization called StEP (Solving the E-waste Problem), formed as a partnership between the United Nations and academic and business organizations, reported re- cently that the annual production of elec- tronic goods worldwide required 320 tons of gold and more than 7,500 tons of silver, with a combined value of $21 billion. At present, just 15% of that is recov- ered, according to StEP, and much of it is processed in less-than-ideal circumstances involving unscrupulous or technically un- sophisticated operations that potentially create as many environmental problems as recycling is intended to solve. The situation seems to offer mine operators, with vast ex- perience in finding, handling and process- ing sometimes difficult-to-handle materi- als, an opportunity to apply their expertise. As shown above, some mining compa- nies are already established as fringe play- ers in the recycling sector, and many are adopting life-of-project strategies for waste management. Anglo American, for exam- ple, explained its policy on its sustainabili- ty webpage: "We're finding new ways to cut waste by re-mining or reusing it. We ap- ply the 'avoid, reduce, reuse and recycle' management hierarchy to ensure the least possible impact on human health and en- vironment during both the operational and post-closure phases. Once waste-reduction opportunities are exhausted, we actively explore the reuse of byproducts." Some common aspects of min- ing make recycling and reuse difficult. Barrick Gold noted that "A number of non-process wastes are generated each year at our operations. These wastes may differ by country and by operation, but typically include scrap metals, waste oils, cans and bottles, spent tires, and office and camp waste. While we try to recycle these wastes as much as possible, this is not always feasible at some of our remote sites or at operations located in countries where recycling is not available. Non-haz- ardous waste that is not recycled is usual- ly landfilled (either in municipal landfills or landfills constructed on the mine prop- erty) or incinerated, on or off the site. Increasingly, less-waste-to-landfill pro- visions are becoming part of a mine's basic permitting package. At the $6.7 billion Donlin gold project in Alaska — a joint venture between Barrick and Nova- Gold — the mine's Integrated Waste Management Plan stipulates that in ac- cordance with state law, management de- cisions that may affect waste generation at the proposed project would be made by considering, in sequence, options starting with waste source reduction and/or recy- cling, followed by waste treatment or dis- posal. In order to accomplish this, Donlin said its plan will ensure that: • Operations that generate wastes would be reviewed to identify opportunities for reducing waste, and these opportu- nities would be implemented when- ever possible. • The properties of materials would be reviewed prior to purchase and an effort made to minimize the use of hazardous materials and those classified as hazard- ous wastes once they can no longer be used for their intended purpose. • Methods for reusing and recycling mater- ials would be promoted and implement- ed whenever possible. • Non-hazardous solid wastes that are per- mitted for disposal on site would be dis- posed of at on-site, permitted, solid waste inert landfills, regulated by the state. • Materials that cannot be managed on site would be sent off site to appropriate facilities for recycling, reuse, treatment and/or disposal. Another aspect of the circular economy model that could increasingly affect dispo- sition of mining-related consumables is Ex- tended Producer Responsibility (EPR), in- formally referred to as the "producer pays" approach in which manufacturers become accountable for the treatment or disposal of post-consumer products, with produc- ers or importers assigned responsibility for organizing and financing waste manage- ment. EPR laws have gained momentum in Europe and Latin America. Legislation (Law No. 20.920) that has gone into effect in Chile, for example, applies to processing oils, electronics, packaging, tires of all siz- es and batteries — foreshadowing possible future legislation in other nations where mining activities are extensive. Giant Tires, Giant Problem Disposal of large and giant-sized tires used on haulage and loading equipment is one of the principal ongoing challenges for both surface and underground mine oper- ators. Giant OTR tires pose a number of problems for recyclers, which makes them up to a hundred or more times more ex- pensive, per tire, to process than the dollar or so it generally costs a recycler to com- pletely reduce a car tire to rubber crumbs. OTR tires' physical characteristics also make them bad choices for landfill disposal. Their low density and hollow centers allow them to "float" upward in landfills, disrupting compaction efforts. Scrapped and buried OTR tires also pose additional problems in case of fire. Once ignited, they're extremely difficult to ex- tinguish and can release pyrolytic oil, ash and smoke, which contain carcinogens, heavy metals and other toxic compounds. They carry the burden of requiring specialized treatment, with per-tire ship- ping and handling costs that can amount to thousands of dollars each, along with the hazards they present to workers during the course of loading, unloading and processing, and the need for extra heavy-duty equipment to cut, cull indi- vidual tire components such as the steel bead bundles, and shred the tire chunks. Because of the low volume of OTR tires available at any single site and the stress they put upon conventional tire recycling equipment, many recyclers are reluctant to process giant tires with existing equipment. And, with estimated capital costs in the $2 million to $4 million range for a tire size-re- duction and shredding facility capable of handling giant OTR tires, many also aren't eager to invest in systems that are expensive yet may be used only intermittently. Under these circumstances, both mining clients and contract recyclers are looking for equip- ment flexibility, efficiency, and transport- ability to service widely scattered sites and minimize shipping and handling costs. If not repairable or retreadable, often the first step in reducing a giant OTR tire prior to shredding is to remove the bun- dles of steel cables that form the tire's bead. Nebraska, USA-based Eagle In- ternational's OTR tire bead remover is a transportable, automated unit that clean-

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