Mining in focus
Trucks on the way to the weighbridge at Wescoal ’ s Elandsfontein Mine in Mpumalanga .
Leon Louw
Masskot Scale
Danie van der Westhuizen , sales director at Masskot Scale
Why should a mine or quarry regard weighbridges as a critical component of its operations ? Measuring product by weight is the only real method to establish input and output and to measure loss control , as theft and corruption are the order of the day .
Is one weighbridge sufficient , and does it matter where it is located ? It will all depend on the size of the mine and logistics . A mine or quarry will need at least one weighbridge before a truck enters the yard , and another one to weigh trucks when they leave the gate . The volume of traffic will determine the number of weighbridges required to prevent unnecessary queuing of vehicles . Most large mines will have at least four weighbridges . Site logistics will obviously determine the positioning , but it is traditionally at the entrance of the mine or quarry .
What advice do you have for a mining company developing a new project in terms of the installation of a weighbridge , considering legal issues , the ideal site , what the best products are , and which type of weighbridge to install ? They need to consider weighbridges that are manufactured and designed locally , and from companies that are reputable in the industry . Preference should be given to companies with ISO accreditation . Weighbridges used in the mining industry should be robust and reliable , with the necessary backup . Automation is becoming more popular , as it eliminates human error and theft .
It is advisable that weighbridges are installed pitless above ground with enough clearance below to make it easy to clean , which is a problem at most mining operations . The onus to keep the weighbridge clean is on the user , as regulated by the National Regulator for Compulsory Specifications ( NRCS ). It is very important to make a decision based on quality and not opt for the most cost-effective solution . Many owners make the mistake of purchasing weighbridges on price rather than quality . Many weighbridge companies do not verify weighbridges in accordance with the SANS specifications , which could affect the client ’ s profitability .
Which weighbridges are best suited for the mining industry ? Mines should use an extra-heavy-duty weighbridge with the least defection under a full load . Weighbridges used in the mining industry are the same for all the different mines and minerals . Weighbridges on coal mines seem to corrode easier , and collieries should consider hot-dip galvanised weighbridges to ensure longevity . Heavy-duty guide rails are recommended for safety .
What does the site preparation for weighbridges entail ? There are various options , which will be determined by the installation . For a permanent position , one would build proper civil foundations . On the other hand , temporary installations only have to be placed on a flat concrete slab . A critical aspect , however , is the sub-base , which has to be designed and built to carry the vertical loads on the load cells .
What is the typical maintenance regime of a weighbridge ? The maintenance regime will also be determined by site conditions , and maintenance can be carried out monthly , three-monthly , biannually , or annually . Personally , I recommend a good service every three month .
What does a mining company need to do to ensure that weighbridges are kept in an optimum condition and to maximise its operational life ? Regular maintenance is a must and keeping the weighbridge and foundation clean goes a long way to prolong the life of the weighbridge .
Which external factors damage the efficiency of weighbridges ? Accumulated dirt , no regular maintenance , damaged cables , poor or bad power supply , and calibrations and verifications not done to the South African National Standards ( SANS ) specifications .
What are the biggest challenges faced by weighbridge suppliers in Africa ? The biggest challenge is to compete with imports from China and unscrupulous operators cutting corners . All South Africans should support “ Made in South Africa ” products , thereby also creating jobs .
www . masskot . co . za danie @ masskotscale . com
[ 30 ] MINING MIRROR JULY 2018