At the quarrying edge

By their very nature, quarries produce high-volume, low-cost material. To run profitable operations, it is critical for quarry owners to find ways to drive efficiencies in every aspect of their operations. Based on that understanding, Danoher has heeded the call for innovation to drive productivity and improve efficiencies.

Situated on the outskirts of Bloemfontein, Bloemspruit Quarry is endowed with a high-quality, sought-after dolorite rock. Acquired by Danoher in January 2017, the operation produces all aggregate sizes, including crusher dust, washed super sand, 7 mm, 10 mm, 14 mm and 20 mm road and concrete stone, base and sub-base materials, as well as specialised products.

Massive investment

During the initial days of Danoher’s ownership, the quarry operated mobile crushing and screening equipment. By November 2017, the company had invested in a new, state-of-the-art static plant. “From the onset, we understood that for us to run a profitable business, we needed to invest in a new, efficient and flexible 250 tonnes per hour (tph) plant, capable of reacting to fluctuating market demand and supporting bespoke customer requirements,” explains Johann van Niekerk, business manager: Bloemspruit Quarry.

Bearing in mind the constant pounding these machines take, it is good to see how these new crushers and screens, being subjected to a stringent maintenance programme, have proven reliable and less prone to breakdowns, thus bringing about maximum plant availability and productivity. In addition, the new equipment, such as the two Metso HP300 cone crushers, contains the most advanced safety features, thus reducing workplace injuries.

“The investment in a contemporary plant was essential for us to drive productivity, plant uptime, efficiency and ultimately run a profitable business,” says Van Niekerk. “We have seen high levels of efficiency, which makes us competitive in such a cut-throat market.”

High-tech wet processing

To meet the high demand for washed sand and washed super sand (a high-end fine sand) used as input material by construction product manufacturers, Danoher invested in a leading-edge 80 tph EvoWash 102 wet processing plant from CDE, becoming the first and only company in the Bloemfontein area to run this type of technology.

Before investing in the CDE plant in 2020, Danoher previously deployed a bucket wheel system. Traditionally, bucket wheel technology was deemed the mainstay for sand production in South Africa. It was cheap to buy, however, a major downside was that a substantial proportion of valuable fine sand would be lost to waste dams. In addition, high and variable moisture content and inaccurate material classification were some of the downsides of the bucket wheel that have been addressed by CDE’s cyclone technology. Unlike the bucket wheel, which relies on gravity as the means of separation, CDE’s cyclone technology entails the use of centrifugal force to classify materials.

“We were aware of the quality variability and sand losses we incurred through the old generation washing plant we had. We therefore had to seek ways to maximise our productivity and efficiency in difficult market conditions. With the investment in the CDE plant, we have seen massive benefits in terms of production, efficiency and reliable quality of the product,” says Van Niekerk.

The CDE cyclone technology has been an important technological advancement for the quarry. Firstly, Danoher is now producing two grades of sand – fine (0 – 1,5 mm) and coarse (0- 5 mm) – compared to only the one grade of sand previously produced by the bucket wheel system.

More importantly, says Van Niekerk, production is up by 30%, while water usage has gone down by 15%. In addition, the quality of the product has improved significantly, thus setting Bloemspruit Quarry apart from competition.

“We have seen a high demand for our sand, particularly from brickmakers. They prefer it because of its high strength and quality. It is made from virgin blue rock, which is also good for the strength of the bricks,” he says.

More efficiencies

To further drive efficiencies, Bloemspruit Quarry makes use of Loadrite belt scale technology from Loadtech. This has proved its worth in maximising equipment value by having it employed in the most efficient manner.

The Loadrite belt scales give plant operators and the management team a range of powerful tools to measure the actual production from screens and crushers, analyse plant and machine downtime.

Apart from these technologies, Van Niekerk and his team also pay special attention to their haul roads. Haul roads maintenance, he says, requires a dedicated focus and is addressed on a continual basis as part of the operational cycle, since good roads improve production, extend tyre life and reduce overall operating costs.

“We haul around 500 m one-way distances from the pit to the processing plant. To optimise our cycle times and our trucks’ fuel-efficiency, and to reduce tyre wear, we have tried to keep our haul roads as straight and free of inclines as possible,” he says.

For its load and haul equipment, Danoher has always preferred Volvo equipment. Two Volvo A30 articulated dump trucks (ADTs) are deployed to haul material from the pit to the processing plant. These are loaded by a Volvo 480 excavator in the pit. Two Volvo wheel loaders, L150 and L190 models, are deployed for stockpiling duties, as well as for loading customer trucks.

“As the Danoher Group, we have always standardised our yellow metal equipment with Volvo. We get a good life out of the machines, while they have over the years proven to be fuel-efficient. Fuel is one of the biggest cost drivers in a load and haul operation, and it is therefore important to pick the best equipment to reduce your fuel bill. After standardising our equipment, spare parts, repair procedures, equipment and repair training have become much less onerous,” says Van Niekerk. “We also get good service from Babcock, which is key to maximising our equipment uptime, productivity and efficiency.”

A strong focus on keeping every part of the business in-house, all the way from drill and blast to load and haul, helps improve efficiencies and reduces the cost of the material for customers. Additionally, this also helps with quality control.

State of the market

Despite the generally depressed market conditions in the South African construction industry, Danoher has grown the Bloemspruit Quarry’s market share which has enjoyed a good market run in the past few months, buoyed by its wide client base and a few road projects in the area. The company’s existing customer base includes aggregate resellers, brickmakers, asphalt plants, readymix plants and property developers, amongst others.

Traditionally, the quarry produces in the region of 25 000 t a month. When we visited the site in October, production and sales had reached record levels.

“The three months between July and September were our best ever. We broke our production record three times in a row. We have been fortunate to have the capacity to ramp up and supply a few road projects in the area, without letting our base volume customers down. We are supplying three projects on the N1 South, the R30 and a new project on the R48,” concludes Van Niekerk.