Effluents and Waste
BMSC has a ‘zero discharge policy’ that eliminates any water discharge.
Solid waste is segregated at two waste handling facilities situated at the camp and salvage yard. In 2016, the accumulated site storage was 58,000 tonnes. General waste management practices include:
• Disposal of non-hazardous waste in an onsite landfill, such as food scraps, safety shoes, hard hats.
• Disposal of hazardous materials, air filters and filter cloth from the concentrates area in the PAG waste facility.
• Onsite incineration of a limited set of items, including medical waste.
• Other wastes (including hazardous items such as batteries) are safely stored onsite pending identification of suitable recycling options.
• Waste oil is sent to a recycling facility in Massawa that blends the material as an additive to heavy fuel oil, consistent with a waste to energy management approach.
In 2016, we milled 2.277 million dry metric tonnes of ore. Of that, 1.900 million tonnes (approximately 83%) went to our tailings management facility with the remainder shipped as copper and zinc concentrates; an increase of 15% over 2015. The tailings have acid generating potential; to address this issue, the facility is fully lined with a high-density polyethylene liner, leak detection system and downstream groundwater monitoring. The tailing and water level is constantly monitored and management performance regularly reviewed by an external expert to ensure we align with international practices.
In 2016, 9.367 million tonnes of material was sent to the waste rock management facility; following standard industry practice, the facility is constructed on unlined compacted rock. Approximately two-thirds of the waste rock has potential to generate acid; this portion is encapsulated within the facility to control acid generation. Monitoring wells are placed on the downstream side of the facility. As a result of the control measures and arid climate, the potential contamination risk is low.
In 2016, seven spills were recorded:
• A bulk 20t bladder used to store emulsion ruptured causing ~20t of emulsion to flow onto the ground within the Explosive Magazine – no emulsion escaped the area. The spilled material was contained with soil bund and contaminated soil removed to temporary storage pending bioremediation treatment. Bisha Mining had already moved from bulk bladders to 1000L IBC totes to avoid such incidents
• While cleaning up spillage on the zinc flotation pump floor, some slurry inadvertently flowed over the bunded wall, contaminating the ground between flotation sections
• While performing normal shutdown at the TMF, a manifold valve began leaking, releasing slurry onto the ground. The material was contained and a few tonnes deposited over a small area
• Four spills related to concentrate trucks rolling over and the containers spilling next to the road. The events occurred: 16 km from Asmara with ~30 t spilled, 85 km from Asmara with ~30 t spilled, 20 km from the Massawa Port with ~20 t spilled, and 60 km from Asmara with ~15t spilled
All spills were successfully cleaned up in an expedient manner, there were no impacts to groundwater or other sensitive environments, no fines were issued and no environmental grievances filed. Bisha Mining continues to work with the trucking contractor to improve performance and minimize risks.
A total of $1,148,815 was spent in 2016 on social and environmental management, including land remediation, environmental monitoring and waste disposal of domestic and industrial wastes. This figure excludes waste management costs associated with tailings or waste rock.