www . refrigerationandaircon . co . za RACA Journal I September 2023 35
Project
In a similar manner , SOMILO awarded BBE Projects a second turnkey contract to build a refrigeration plant at the Yalea South dedicated downcast ventilation hole in 2021 . This time SOMILO requested that all equipment supplied by BBE Projects must be compatible and interchangeable with the existing refrigeration plants to minimise spares holding and to allow the mine to implement the same corrective and preventative maintenance schedules used at the existing plants .
“ Standardisation of equipment was another crucial requirement , given the remote location of the mine . Working in Africa presents unique challenges due to remote locations and the need for self-sufficiency . By utilising standardised components and maintenance procedures , the mine could streamline operations , minimise spare parts inventory , and ensure ease of future maintenance ,” says Andhee .
The new refrigeration plant capacity is 8MWR and is smaller than the existing refrigeration plants , but with space reserved and design provisions made to expand the refrigeration system in future if required . The new refrigeration plant also has many improvements compared to the existing plant . These innovations were brought about during meetings and consultation with mine employees that maintain and operate the refrigeration plants . The SOMILO ventilation team completed an extensive ventilation study with aid of mine ventilation simulation software .
The most notable innovation is the five-metre diameter steel inlet duct that connects the bulk air cooler to the dedicated downcast ventilation hole complete with selfclosing dampers positioned directly above the shaft that vent shockwaves that occur during certain times of day due to blasting underground . The damper blades are of a relatively light construction allowing the blades to open with little pressure and close using adjustable counterweights .
The refrigeration machine is an 8MWR dual-compressor York YD with R134a refrigerant , housed in a plant room erected from steelwork that was designed , shop detailed and fabricated in South Africa . Dual compressors were selected to halve the maximum instantaneous start-up current of the refrigeration machines thereby mitigating the possibility of de-stabilising the mine ’ s power grid . The mine generates its
Avinash Andhee , senior project leader and mechanical engineer at BBE .
Avinash Andhee ( BBE Snr Project Engineer ), Cheick Oumar Konate ( SOMILO Technical Services Manager ), Cheick Oumar Coulibaly ( SOMILO Snr Ventilation Engineer ), Gabriel Kone ( SOMILO Underground Mining Manager ), Dramane Kane ( SOMILO Chief Ventilation Engineer ), Humphrey Maluleke ( BBE Site Manager ), Soumaila Keita ( SOMILO Ventilation Engineer ) – From right to left .
Inside electrical room .
www . refrigerationandaircon . co . za RACA Journal I September 2023 35