As technological improvements affect every part of modern day life, it is also imperative for quarries, as old school as they are thought to be, to follow the wave. SPH Kundalila, a Cape Town, South Africa-based crushing and screening expert, seems to be heeding this call.
Part of the Raubex Group, SPH is a mobile crushing and screening specialist with related earthmoving, plant hire, materials handling, as well as loading and transportation divisions. Away from its core crushing and screening contracting business, it also operates several of its own quarries.
At its Bridgetown Dolomite Mine (BDM) in Morreesburg, Cape Town, efficiency is being driven in every sense of the word. A pillar of the quarry’s efficiency drive is the recent adoption of an Aquila Drones drone data management system via the AQRVS fixed-wing drone that is helping site manager Louis Pretorius with effective stockpile management and aerial surveys. SPH started engaging the services of supplier MJ Geomatics in November 2015 to implement the Aquila Drones’ drone data management system, and to date Pretorius is impressed with the results.
Rightly so, measuring the volumes of all stockpiles can now be done in just 10 minutes using this system. Previously, this task could take as much as two days or more of strenuous GPS work to cross-section those piles.
The process starts with labelling of all the stockpiles to know what material lies where before you fly the drone over the stockpiles. The drone, through scanning, can tell you the exact size of the stockpile. This allows for easy management of production and planning accordingly.
Apart from stockpile management, the Aquila Drones’ drone system also offers detailed aerial surveys. Aerial surveys help with sound mine planning, especially determining where you are going to blast next, haul road structure, elevation and bench heights.
Drone measurement is being done every two months, mainly because the stockpile levels don’t change much during that period. This is over and above the fact that drone data collection is costly than conventional GPS work. Typically a drone survey costs as much as ZAR 7,500 (US$460) per survey compared to a GPS one that would come in at about ZAR 4,000 ($263).
But, upfront cost aside, Johan le Roux, business development manager at SPH, believes drone data collection is worth every cent. By switching to drone data collection, a quarry can reduce the required man-hours by approximately 60% while producing results within 2% of manual measurement.
BDM is a metallurgical dolomite mine. Total production for this product is about 14,000tonnes/month. It is supplied to steel producer Saldanha Steel.
Production process starts with drilling and blasting in the pit. This is done once a month and has been outsourced to contractor Blasting and Excavating. Blasts are kept relatively large, aiming between 35,000 and 40,000tonnes/blast. From here, two Caterpillar 340 excavators load four Bell articulated dump trucks (3x B25D and one B18D) that haul from the pit to the BDM plant, the main crushing and screening plant on site.
The plant comprises a primary jaw crusher and a secondary cone crusher. When ADTs tip, material runs in a linear fashion through the primary crusher where it’s crushed into 40mm sizes, before going through the secondary cone and through a washing screen and onto the stockpile.
A Pilot Crushtec screen and a vertical shaft impactor, feeding off the main BDM plant, form part of a plant which produces agricultural lime. “During the summer months we produce agricultural lime for farmers in the area. Production period is basically from September to March,” says Jean Martin, manager at SPH Kundalila, adding that production capacity for this product is about 5,000tonnes/month. While production peaks between January and March, the bulk of the material sells between January and April when farmers prepare their land.
Management is also leaving no stone unturned in its quest for efficiency. To further boost margins, they are continuously looking for alternative markets to further increase product portfolio. This approach has seen an expansion of products to a total of 17.
Besides metallurgical dolomite and agricultural lime, a total of 15 aggregates are produced. These include three concrete aggregate sizes of 37.5mm, 26.5mm and 22mm; four road stone sizes of 19mm, 13.2mm, 9.5mm, 6.7mm; three crusher sands of 5mm, 6mm and 8mm sizes; base material of G1, G2 and G3 sizes; as well as sub-base material in G5, G6 and G7 sizes.
With its contract crushing and screening background, the company also understands that a reliable and well maintained fleet not only increases operational efficiency, but provides a safer working environment.
BDM benefits from a companywide focus on premium brands, as well as strict fleet replacement and maintenance programmes. At this site, SPH is running two 340 Caterpillar excavators; one 329 Cat excavator with a hammer fitting; four Bell ADTs; four Cat loaders (three 950s and one 938 model); two Terex Finlay screens; one Cat 140G grader and a Cat D6 dozer. The fleet benefits from a strict maintenance regime. Trackless mobile machinery is serviced at 250-hour intervals and receive a major service at 1,000 hours.
GRADING
1 x Caterpillar 140G grader
DOZING
1 x Caterpillar D6 dozer
LOADING
2 x Caterpillar 340 excavators
3 x Caterpillar 950 wheeled loaders
1 x Caterpillar 938 wheeled loader
HAULING
3 x Bell B250D articulated dump trucks
1 x Bell B18D articulated dump truck
CRUSHING
1 x Modular plant (jaw + cone)
1 x Pilot Crushtec International vertical shaft impactor
SCREENING
2 x Terex Finlay screens
1 x Pilot Crushtec International screen
A strong focus on fleet reliability is not only unique to this site. SPH owns a fleet of 350 earthmoving equipment items, says Le Roux. It claims to be the largest owner of mobile screens and Cat 950 loaders in Africa. It has over 100 units of the Cat 950 model in its fleet. “We find these machines long-lasting, powerful, productive and versatile for our material handling applications,” says Le Roux.
For its screening needs, SPH believes in Terex Finlay, and as a result has about 40 units from the UK manufacturer. For its hauling needs, the company trusts Bell Equipment’s ADTs and has more than 60 of these units in its stable. “We have tested all the different brands in the market over the years. We stick to these brands because we believe they are value for money. The premium we pay upfront is paid back through reliability and safety,” says Le Roux.
Buying equipment is one thing, but knowing when to replace it is quite another. Depending on a piece of equipment, SPH replaces its equipment at about 16,000 to 18,000 hours. “Newer machines work better and are fuel-efficient,” says Le Roux.
Aquila Drones for quarrying
Aquila Drones is a South African company which develops and builds unmanned aerial vehicle (UAV) solutions, customised to each client’s needs. The Aquila Drones product line-up comprises in-house designed and developed solutions for multi-copter as well as fixed wing UAVs. In all cases a total turnkey solution is presented to the client, with the associated training and support to effectively apply the system.
Founded by Johan Janse van Rensburg, an aeronautical/mechanical engineer with more than 20 years of experience in aircraft systems design, development and certification, the core of Aquila Drones team is from an aeronautical and military background.
Aquila Drones specialises in turnkey solutions for multiple UAV applications. One of many services offered by Aquila Drones is aerial mapping and survey solutions, and this has been mostly in quarries and open cast mines.
Using high-tech multi-rotors and fixed-wings drones to collect aerial images, 3D models and orthophotos are delivered. The solution utilises inexpensively acquired high-resolution photography, digital processing of images producing DSM, DTM, textured mesh and georeferenced point cloud data for virtual survey purposes. This is said to be done at a cost not achievable with traditional ground or other airborne methods. Model accuracy can be as low as 2mm per pixel with absolute georeferencing. Stockpiles are measured with a turnaround time from of less than 48 hours.
