Some four years ago, Danoher concluded the deal to purchase three commercial quarry assets from cement giant, PPC, in Botswana. The deal included three quarries – Kgale, Mokolodi and Francistown. Following the conclusion of the deal, all three operations required a bit of attention, especially the static processing plants at Kgale and Francistown.
From the onset, says Danoher, the company put more attention on Kgale Quarry which, by virtue of its location in the Botswanan capital of Gaborone, constituted the bulk of Danoher’s commercial quarrying business in the country. At the time of the acquisition, the Kgale plant had reached the end of its economic life, with limited scope for extension as the previous owners were preparing for a planned closure of the quarry.
“The plant was generally old and needed replacement. For example, the crushers were old-school technology, which affected efficiencies and safety. The conveyors were also old and worn out. Consequently, a decision was taken to invest in a completely new plant. This upgrade period required a careful balance between maintaining reliable, high-quality production output and progressing steadily with the upgrade project. It took us about six months to decommission the existing plant. During that time, we were running a 100% mobile crushing and screening operation and at one point we had three trains on site to meet the required production capacity,” explains Danoher.
Four stages
The installation of the new plant commenced soon after the decommissioning of the old static plant. While Danoher managed to sell off some of the components, the majority of the old plant was scrapped.
The new plant installation was executed in four stages. First up was the tertiary section, which was initially fed by a mobile train upon its completion. The tertiary setup comprises a tunnel that goes into a Techroq 7’ x 20’ screen, which works in close circuit with a Metso HP400 cone crusher.
After the completion of the tertiary section, the secondary setup was up next, which is basically a Metso HP300 cone crusher with its own surge pile. The third leg of the project saw the installation of the primary section – a Metso C125 jaw crusher and a 90-m stacking conveyor that feeds a dedicated intermediary stockpile (ISP). The last section, completed at the end of 2024, was the vertical shaft impact (VSI) crushing circuit. This section comprises a Twister VS350 VSI crusher from Pilot Crushtec International in close circuit with a 6’ x 16’ MVT screen.
Given that the four stages were not implemented immediately after one another, and the fact that Danoher maintained 60 000-70 000 tonnes per month (tpm) production during the plant upgrading phase, total completion of the whole project took some 24 months in total.
“While several components, such as the Twister VS350 VSI crusher, and the screens and conveyors were sourced new, some of the equipment such as crushers were second-hand units that we sourced from Africa and Europe and refurbished in-house at our workshop. The total capital investment in the new plant was about R80-million,” explains Danoher.
Significant gains
The investment in the new plant has ushered in a new era in productivity, efficient operation, flexibility, and safety. In terms of productivity, the new plant can produce 80 000 tpm working a single shift, up from about 30 000 tpm capacity on the previous plant. The new capacity allows Danoher to meet monthly demand, which is averaging around 75 000 tpm at the moment, without having to supplement with mobile trains.
Removing the need for mobiles, says Danoher, reduces operating costs significantly. While mobile units offer flexibility for short-term projects, the static plant, powered by the electrical grid, is more efficient and cost-effective than the diesel engines used in mobile units, both in terms of operation and maintenance.
“The flexibility of this plant, especially given the variability in our material, is another major operational gain for us,” explains Danoher. “In our pit, we mine both granite and dolerite and these have to be processed separately to meet different customers’ needs. Generally, our brick and block customers, as well as their concrete products manufacturer counterparts, prefer granite because of its ‘pinkish’ colour. Conversely, the roads and asphalt clients prefer dolerite because of its strength.”
From the onset, the plant was designed to allow for switching between materials with ease. To achieve this, each section – primary, secondary and tertiary – comes with its own surge pile. The flexibility allows Danoher to adapt to market changes by quickly switching between products, thereby minimising downtime, reducing waste, improving resource utilisation and increasing responsiveness to customer demands.
The installation of new-generation crushers ensures better safety on site. HP cone crushers from Metso, for example, ensure safety through features such as hydraulic unblocking systems for sudden stoppages and automatic feed rate control to maintain optimal material levels and prevent blockages.
State of market
Commenting on the state of affairs in Botswana, Danoher says the “market is relatively stable”, despite a constrained economy due to the global slowdown in the diamond market, a major source of revenue for Botswana. Consequently, some of the proposed construction projects have been postponed or cancelled due to lack of funding.
In addition, says Danoher, there have been some significant fuel and electricity price increases in Botswana, which have generally put a lot of pressure on businesses. “We continue to place major emphasis on our efficiencies to ensure that we can absorb some of these cost shocks. The new plant allows us to do exactly that without having to pass all the costs to our customers because it is not sustainable. Businesses are already suffering from inflationary pressures and we are in a position to shield our customers from that by means of being better at what we do,” says Danoher.
However, like any other commercial operation, Danoher’s Kgale Quarry remains pretty much buoyant, largely sustained by a combination of month-to-month customers and projects. The quarry currently averages around 75 000 tpm, confirms Danoher, with manufactured sand being the biggest seller to date.
“The sand market is largely driven by month-to-month customers – brick and block makers, paving brick makers and concrete product manufacturers in general – whose market is in turn driven by town council upgrades and the seemingly thriving residential property market in Gaborone,” concludes Danoher.
