News

Transfer Points Can Contribute To High Maintenance Costs

Although transfer points potentially contribute to some of the highest maintenance costs on a mine, engineers seldom view transfer systems as a critical element of the minerals processing system.

So says Mark Baller, managing director of Weba Chute Systems, who maintains that transfer points — by the very nature of their application — should be viewed with the same level of importance as any other machinery in the minerals processing cycle.

"The uncontrolled discharge of bulk materials through conventional chutes has a history of escalated maintenance and replacement costs, not least of which can be attributed to excessive wear and other related problems," Baller says. "All of this adds up to unnecessary expenditure and a headache for the engineers concerned.

"Numerous successful installations of Weba Chute Systems have proved that the correct use of our streamlined, scientific approach to the dynamics of bulk materials handling greatly reduces the problems associated with conventional transfer chutes and results in significant cost savings."

Each Weba Chute System is custom designed for a specific application, taking into account factors such as belt width, belt speed, material sizes and shape and throughput. Baller says there are numerous advantages to be gained from this locally developed transfer system which, when introduced on a new project, achieves the optimum design configuration for the application with the best belt cleaning arrangement and optimum selection of belt type and size. In addition, spillage can be completely eliminated.

Further benefits that apply equally to retrofitted Weba Chute Systems and new projects alike include up to 80% reduction in material degradation, greatly reduced levels of dust and noise, reduced production losses owing to fewer blockages, significantly reduced spillage and vastly improved safety levels.

Easy access is provided for inspection and maintenance purposes and the system does not require ongoing supervision, again representing a saving in manpower and related costs.

Baller says Weba Chute Systems should not be compared to conventional chute systems but rather seen as an improved alternative or "upgrade", because they adopt a completely different and unique approach to control and handling of bulk materials. For instance, the system uses a "supertube" with a cascade scenario, where 95% of the material runs on material at all times.

"When one looks at this process in slow motion, it becomes apparent that the bottom layer of particles in the product stream move in a tumbling motion and do not slide down the chute," he explains. "This results in significantly reduced wear and in many cases the lip remains completely covered by material and never needs replacement."

This manner of controlling material movement is taken a step further by designing the internal angle of the transfer chute in such a way as to match the product discharge velocity with the belt speed, which either completely eliminates or greatly reduces spillage.

Extensive experience and technical expertise, coupled with applications knowledge, has positioned Weba Chute Systems as the leader in its field. The Weba Chute System design is accomplished using sophisticated 3D computer software. Data received from the customer is always verified, and in many instances Weba Chute Systems' highly skilled personnel are in a position to make cost saving recommendations.

The quality of the manufacturing process is strictly controlled by the company's procedures which are in line with their ISO 9001:2008 certification. Performance guarantees, set in accordance with operational and application parameters, are provided with all Weba Chute Systems.

M&J Engineering to Supply First Weba Chutes In a Shiploading Application

M&J Engineering is supplying the first Weba Chute Systems in a shiploading application for installation on Portnet's Shiploaders 1 and 2 at the Port of Saldanha. This follows the successful installation of Weba Chutes at Portnet's iron ore handling plant some time ago.

"Designed for a transfer of 10 000 tph of iron ore, the two boom transfer chutes feature a levelling device that keeps them vertical at all times during the luffing of the boom in a range from 14 degrees to 5 degrees. This will minimise spillage and blockages, and ensure an even load of iron ore onto the boom conveyor," says Alwin Nienaber, technical director of M & J Engineering.

This conveyor has a belt size of 1 650 mm and runs at a speed of 4 metres per second. Bulk density of the iron ore varies from 2.3 to 3 tons per cubic metre and maximum lump size is 40 mm, with a moisture content of about 3%.
Also at the Port of Saldanha, on a contract awarded directly by Portnet, M&J Engineering is currently upgrading the moving head chutes to ensure these conveyor transfer points will be able to cope with the 10 000 tph ship loader capacity.

"The existing conventional chutes had been experiencing ongoing problems relating to spillage and blockages," M&J Engineering's Ted Cruickshank says. "We've been contracted to design and fabricate Weba Chutes for this application and to re-instate all the required instrumentation and piping services.

"To prevent future blockages we've carried out Fine Element Analysis (FEA) on the chutes to determine the flow of the iron ore and verify the chutes' capability to handle 10 000 tph and to load this material central to the ongoing conveyor."

Both projects will be completed by the end of August 2012.

Custom designed
Each Weba Chute System is custom designed for a specific application, taking into account factors such as belt width, belt speed, material sizes and shape and throughput. Cruickshank says there are numerous advantages to be gained from this locally developed transfer point system which, when introduced on a new project, achieves the optimum design configuration for the application with the best belt cleaning arrangement and optimum selection of belt type and size. In addition, spillage can be completely eliminated.

Further benefits that apply equally to retrofitted Weba Chute Systems and new projects alike include up to 80% reduction in material degradation, greatly reduced levels of dust and noise, reduced production losses owing to fewer blockages, significantly reduced spillage and vastly improved safety levels.

Easy access is provided for inspection and maintenance purposes and the system does not require ongoing supervision, again representing a saving in manpower and related costs.

Cruickshank cautions that Weba Chute Systems should not be compared to conventional chute or transfer point systems, but should rather be seen as an improved alternative or "upgrade", because they adopt a completely different and unique approach to control and handling of bulk materials. For instance, the system uses a "supertube" with a cascade scenario, where 95% of the material runs on material at all times.

"When one looks at this process in slow motion, it becomes apparent that the bottom layer of particles in the product stream moves in a tumbling motion and does not slide down the chute," he explains. "This results in significantly reduced wear and in many cases the lip remains completely covered by material and never needs replacement."
This manner of controlling material movement is taken a step further by designing the internal angle of the transfer chute in such a way as to match the product discharge velocity with the belt speed, which either completely eliminates or greatly reduces spillage.

Extensive experience and technical expertise, coupled with applications knowledge, has positioned Weba Chute Systems as the leader in its field. The Weba Chute System design is accomplished using sophisticated 3D computer software. Data received from the customer is always verified, and in many instances Weba Chute Systems' highly skilled personnel are in a position to make cost saving recommendations.

The quality of the manufacturing process is strictly controlled by the company's procedures which are in line with its ISO 9001:2008 certification. Performance guarantees, set in accordance with operational and application parameters, are provided with all Weba Chute Systems.

38 Weba Chutes to Black Rock

M&J Engineering is close to completing an order for the supply and installation of 29 of its innovative Weba Chute Systems at Assmang Manganese's Black Rock Mine Operations, about 80 kilometres north-west of Kuruman in the Northern Cape. The company is undertaking all the site surveys as well as the design, fabrication, removal of the existing chutes, installation of the Weba Chute Systems and commissioning these units.

At the same time, M&J Engineering is about to enter the fabrication phase on a separate order for Black Rock Mine for nine Weba Chute Systems of varying configuration as part of an upgrade to the mine's tippling conveyor and silo feed system.

The 29 new Weba Chute Systems are replacing the mine's existing conventional transfer points. These have been in operation for about two years, but are not performing to the required specifications.

"The Black Rock team called us in to survey all 29 transfer points and our design consequently reflects throughput increases and greatly reduced potential for blockages," M&J Engineering project manager, Ted Cruikshank, says. "Close co-operation between our team and Black Rock is ensuring that the chutes are installed at specific times to achieve minimum downtime."

The Weba Chute Systems will carry ROM material ranging in size from minus 150 mm. On the 900 mm ROM conveyor, bulk density is 2.4 tons per cubic metre at an average of 900 ton per hour with a conveyor speed of 2.7 metres per second. The conveyor is moving maximum size slabs up to 300 mm.

The transfer points vary in operation from bin discharge, silo discharge, plant feed, primary feed and discharge, secondary feed and discharge, tertiary feed, desliming screen discharge and product bin chutes. The product bin chutes will handle material with a maximum size of minus 75 to plus 6 mm, and this size distribution is all saleable products.

M&J Engineering first supplied a skip discharge Weba Chute System to Black Rock 12 years ago and Cruikshank reports that the chute is still working well. The company has also supplied Weba Chute Systems to other Assmang operations including Khumani, Beeshoek, Machadodorp and Cato Ridge.

Regardless of belt speed, belt width, material size, shape or throughput, the Weba Chute System eliminates the problems associated with conventional transfer chutes and provides cost effective, productivity enhancing and environmentally friendly solutions.

Recognising the many benefits associated with Weba Chute Systems, market acceptance has reached a high point with over 3000 chutes currently doing duty in the bulk materials handling industry worldwide. Although certain technology is common throughout Weba Chute Systems, each is contextually fine-tuned and hot commissioned to achieve optimal results at each customer site.

Transfer Points Can Contribute to High Maintenance Costs

Although transfer points potentially contribute to some of the highest maintenance costs on a mine, engineers seldom view transfer systems as a critical element of the minerals processing system.

So says Mark Baller, managing director of Weba Chute Systems, who maintains that transfer points — by the very nature of their application — should be viewed with the same level of importance as any other machinery in the minerals processing cycle.

"The uncontrolled discharge of bulk materials through conventional chutes has a history of escalated maintenance and replacement costs, not least of which can be attributed to excessive wear and other related problems," Baller says. "All of this adds up to unnecessary expenditure and a headache for the engineers concerned.

"Numerous successful installations of Weba Chute Systems have proved that the correct use of our streamlined, scientific approach to the dynamics of bulk materials handling greatly reduces the problems associated with conventional transfer chutes and results in significant cost savings."

Each Weba Chute System is custom designed for a specific application, taking into account factors such as belt width, belt speed, material sizes and shape and throughput. Baller says there are numerous advantages to be gained from this locally developed transfer system which, when introduced on a new project, achieves the optimum design configuration for the application with the best belt cleaning arrangement and optimum selection of belt type and size. In addition, spillage can be completely eliminated.

Further benefits that apply equally to retrofitted Weba Chute Systems and new projects alike include up to 80% reduction in material degradation, greatly reduced levels of dust and noise, reduced production losses owing to fewer blockages, significantly reduced spillage and vastly improved safety levels.

Easy access is provided for inspection and maintenance purposes and the system does not require ongoing supervision, again representing a saving in manpower and related costs.

Baller says Weba Chute Systems should not be compared to conventional chute systems but rather seen as an improved alternative or "upgrade", because they adopt a completely different and unique approach to control and handling of bulk materials. For instance, the system uses a "supertube" with a cascade scenario, where 95% of the material runs on material at all times.

"When one looks at this process in slow motion, it becomes apparent that the bottom layer of particles in the product stream move in a tumbling motion and do not slide down the chute," he explains. "This results in significantly reduced wear and in many cases the lip remains completely covered by material and never needs replacement."

This manner of controlling material movement is taken a step further by designing the internal angle of the transfer chute in such a way as to match the product discharge velocity with the belt speed, which either completely eliminates or greatly reduces spillage.

Extensive experience and technical expertise, coupled with applications knowledge, has positioned Weba Chute Systems as the leader in its field. The Weba Chute System design is accomplished using sophisticated 3D computer software. Data received from the customer is always verified, and in many instances Weba Chute Systems' highly skilled personnel are in a position to make cost saving recommendations.

The quality of the manufacturing process is strictly controlled by the company's procedures which are in line with its ISO 9001:2008 certification. Performance guarantees, set in accordance with operational and application parameters, are provided with all Weba Chute Systems.

Three Weba Chutes Systems Delivered to Lumwana

Following an order placed by Bateman Engineered Technology (BET) in 2011, bulk materials handling company Weba Chute Systems has delivered three transfer chutes to Barrick's Chimiwungo Development Project in Zambia for installation in the raw materials handling section of the plant. Commissioning will take place at the end of the second quarter of 2012.

All three chutes will operate on the same line, handling primary crushed ore up to 250 mm with a maximum lump size of 400 mm at an average throughput of 5140 tph.

The first chute will transfer material from a 1800 mm wide conveyor at 3.15 metres per second to a 1350 mm outgoing conveyor at 5.5 metres per second. The second trifurcated chute will move material from here to either of two receiving belts at the same width and speed or bypass to a bin to cater for the feed conveyor coasting time during a power failure or emergency stop. The third chute will transfer material from the incoming 1350 mm belt, which it receives at 5.5 metres per second to an outgoing 1800 mm belt travelling at a speed of 3.17 metres per second.

Alwin Nienaber, Weba Chute Systems technical director, says the design of the second chute took into account the client specification that changeover from normal operating conditions to bypass mode must be achieved within 5 seconds. This resulted in a trolley speed of 400 mm per second.

"In applications like this where abrasive materials such as copper ore are handled and require regular maintenance as well as planned chute maintenance intervals, Weba Chute Systems are proven to reduce operating costs per ton," he says. "This is possible because the chutes not only require substantially less maintenance, but their design also eliminates the downtime associated with conventional chute design and the typical lack of attention traditionally given to transfer points at the plant design stage."

Weba Chute Systems control the direction, flow and velocity of the calculated volume and type of material in each application, also taking into account belt width, belt speed, material sizes, shape and throughput.

"A correct and appropriate chute design is critical and it is imperative that all these factors are taken into account," Nienaber says. "It's not just about manufacturing a chute. We look at both current and historical data in order to fully understand exactly what the customer requires. We look at the most important factors that need to be addressed in a particular application and this, in some cases, could be as simple as reducing dust and spillage."