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