Shamva Mine: Overcoming Challenges to Maintain Consistent Operations
Shamva Mine is currently operating as an underground mine and employs innovative Sublevel Open Stoping mining methods that are tailored to the geometry of the ore body.
Sublevel Open Stoping is a mining method that is known for its efficiency and safety. The method involves mining the ore body in horizontal slices or levels. The levels are drilled and blasted, and then the broken ore is transported to the surface for processing. The approach is especially suited for the extraction of narrow veins and lodes that can be found in underground deposits.
This was said by Shamva Mine General Manager Engineer Gift Mapakame in a technical interview with Mining Zimbabwe at a recent tour of the gold mine by journalists from various Media houses. Eng Mapakame spoke about the challenges and solutions the gold miner goes through to maintain consistent operations.
“Shamva Mine is currently operated as an underground mine which employs Sublevel Open Stoping mining method applied in Longhole Stoping and Underhand Stoping variants. The variants are utilized to respond to the geometry of the ore body. Underhand Stoping is opted when the ore block requires more selective mining particularly in narrow veins to manage dilution whereas long-hole is opted when the block is more regular, broad and more continuous in mineralization. The latter earns itself to massive ore generation whereas the former limits ore generation into smaller drill & blast cycles,” Mapakame said.
To ensure the safety of personnel and protect the environment, Shamva Mine adheres to ISO 45001, 14001, and 9001 standards according to Makapakame. He said the company’s Safety Health Environment and Quality Management system is designed to achieve zero harm and manage risks effectively. The mine continuously improves its systems by learning from unfortunate incidents, aiming for optimal safety and environmental sustainability.
“Shamva Mine has a Safety Health Environment and Quality Management system that conforms to ISO 45001, 14001 & 9001 standards for Occupational Health, Environmental Management and Quality Management. The objective of the system is to achieve zero harm to personnel, the environment and stakeholder ecosystems. The implementation framework ensures that we are able to identify hazards and risks within our siting of works including those arising as a result of our operations and put controls to eradicate them or manage them to acceptable levels. By so doing, we believe we can tackle all potential risks that can affect our employees and environment. Yes, sometimes we have unfortunate incidents, but our spirit is to draw learning points from these unwanted events and ensure that we continuously improve the systems in place,” continued Mapakame.
Power distribution at Shamva Mine is designed per ZESA requirements and standards. However, the mine is exploring technology options to replace pneumatics as it is considered costly to run Mapakame said. Currently, the mine utilizes pneumatic-powered equipment for drilling and portable emulsion pumps for blasting operations.
“Design of Shamva Mines’ electrical power distribution conforms to ZESA requirements and standards. Shamva Mine utilizes pneumatic-powered equipment for drilling. This is inclusive of Underhand stoping and long-hole stoping as well as underground development. Subsequent blasting operations are carried out with Underground Bulk Emulsions which is handled using portable emulsion pumps. The mine is currently exploring technology options to replace pneumatics as it appears costly to run,” Mapakame opined.
Water for Shamva Mine is sourced from Mazowe River through an abstraction permit issued by ZINWA. The water is distributed to underground operations, where it is utilized and discharged into a drainage system. The mine has implemented settlers to trap suspended solids, allowing clear water to be pumped out for further treatment and recycling. Excess water is discharged into nearby streams according to relevant permits.
“Shamva Mine utilizes water from Mazowe River on an abstraction permit issued by ZINWA. The mine has a pump station located on the river bank 6km from the mine which feeds reservoirs onsite. The water is distributed into underground operations where it is utilized and discharged into cascading drainage and dewatering system. There are drains on each underground level which collect water and channel it down to settler silos which are established at mid-point depth and at the bottom of the mine. The settlers trap suspended solids allowing clear water to be pumped out of the underground operations. The water is received at the reservoirs on the surface where it is further treated for sediment and recycled back into the underground operation. Excess water particularly in the rainy season is discharged into nearby streams through the relevant discharge permit requirements. The water pumped from Mazowe is thus makeup water required to compensate losses in the closed recycling loop,” Mapakame continued.
Shamva Mine has the potential for mechanization and automation, particularly in steep ore bodies. The mine is exploring the use of battery-powered mobile equipment to improve safety and efficiency, as well as to replace traditional and costly pneumatic-powered equipment.
Adherence to legislation and all applicable requirements is important for Shamva Mine. They have a robust Operational Control Framework in place and undergo rigorous internal and external audits to ensure compliance.
“Compliance to legislation and all applicable requirements constitutes our Licence to operate. At baseline survey, the mine has identified the legislative landscape that governs its operations and thus all our activities are structured in an Operational Control Framework which adapts to the legislative requirements as a pre-requisite to help dictate the resource requirements and methodologies applicable. To ensure adherence, we have a rigorous audit protocol administered internally and externally to assist in identifying gaps in compliance and subsequently closing them out,” Mapakame said.
Despite these efforts, Shamva Mine faces challenges that affect its ability to maintain consistent and predictive operations. One of the major concerns is the availability of power and potential load shedding, which disrupts operations. While the mine has a diesel-powered backup facility, it is not sufficient to sustain the entire operation and is costly to run due to high diesel consumption. Additionally, the pricing model for local supplies creates difficulties in controlling operating costs due to the perceived foreign exchange rate impact.
In conclusion, Shamva Mine strives to overcome challenges and maintain consistent operations while prioritizing safety, environmental sustainability, and compliance with regulations. The mine aims to improve efficiency through mechanization and automation and continues to adapt to the evolving operational landscape.