MechChem Africa February 2019

⎪ Materials handling ⎪

Spores and contaminants associated with dust and aerosol can adversely impact human health, causing a range of issues from respiratory infections to toxic exposure. In the interest of workplace health and safety,Weba Chute Systems has developed and patented certain flow designs for its equipment that keep dust levels as low as possible. Chute system reduces risk of dust contamination

C hutesystemsprovider,WebaChute has invested in the latest technol- ogy to profile the dust secretion of conventional chutes used inmines, showing how the custom-designed Weba chutes address this occupational hazard. “Dust particles around 0.3 μm in size have the most serious impact on human health. In particular, the transport of metals and metalloids in atmospheric dust around min- ing operations may lead to increased human exposure to toxic contaminants,” says Izak Potgieter, health and safety officer for Weba ChuteSystems, whonotes that dust secretion has been a major issue for most mines. “When these mines invest in a Weba Chute System solution, we apply our latest technology toprofile thedust secretionof the conventional chute, and compare this to the Weba chute once we have installed it. Potgieter notes thatWebaChute Systems has monitored and measured dust secretion at numerous plants and sites in order to do a full analysis of dust particles being generated during the transportation of minerals on con- veyors and through chutes.

“Using a handheld dust meter, we are able to gather data in 30 second intervals, with 0.003 seconds per measurement over a duration agreed with the customer,” he says. The data is then profiled into a scatter plot that considers factors such as lump size, belt speed, relative humidity, wet-bulb tempera- ture, wind conditions and material type.” He says that a normalised profile can be created after the scatter data has been calculated, showing dust versus lump size in increasing order. This plots the data in such a way that the customer can easily reference theprevailingdustlevelsagainstthelumpsize. “The lump size will affect the dust levels, based on size, speed and material type – and factors are calculated for each of these aspects,” he says. “Belt speed will also affect the dust levels, depending on the tonnage per hourtravellingthroughthechute;thetonnage per hour is in turn linked to the material type and lump size.” He says that by ensuring that its chutes are engineered anddesigned according to the specific transfer and ore application, Weba Chute Systems can ensure ultimate flow

Dust particles are measured at a transfer point with the Weba Chute Systems handheld system. Dust accumulation impacts on work health and leads to be decrease in productivity. control, managing the velocity and impact of the material and reducing wear and tear on the chute. “As well as reducing spillage, noise and conveyor damage, our flow designs keep dust levels as low as possible to reduce the impact of this hazard,” Potgieter concludes. q

WEBA CHUTE saves costs, at diamond mine

Weba Chute Systems’ recent solution at a diamond mine in Botswana tackled the issue of large particle sizes to ensure more uptime for the customer’s operation. The mine had been faced with replacing transfer chutes almost every threemonths due to large kimberlite lump sizes of up to 1 200 mm being fed via an apron feeder onto a griz- zly feeder. This lack of material control had resulted in high impact onto the conveyor belt, damaging the conveyor and causing considerable spillage, resulting in the conveyor belt having to be replaced about every quarter as well. The added expenditure and lost productivity meant in- creased operating costs for the plant, which eventually led to a decision to address the total material transfer system. The technical team fromWeba Chute Systems assessed the challenges being faced and, in close collaboration with the mine, engineered a material handling solution. “Dealing with challenging applications – and in particular uncontrolled material flow – is something we are known for. We are often called in to assist plants where a standard one- size-fits-all solution has proved inadequate to their specific material handling needs,” says Dewald Tintinger, technical

manager at Weba Chute Systems. “Custom-engineered transfer points are designed to deal specifically with individual materials handling appli- cations, offeringmajor advantageswherebasic chute systems have failed,” he says.

InWeba Chute Systems’ purpose-de- signed solution for the diamond mine, an integralswingmechanism–engineeredto guide large lump sizes through the trans- fer point at a controlled velocity – reduces the impact ondownstream equipment, he explains. “The next chute in the process flowtherefore no longer has to deal with excessive impact,” he says. The combination of this

and other innovations has significantly reduced mate- rialimpactontotheconveyor and substantially increased chute and belt life. q

February 2019 • MechChem Africa ¦ 17