Kroondal Platinum Mine, located 120 km north-west of Johannesburg on the western limb of the Bushveld Complex, is one of the lowest cost producing underground platinum mine in the world thanks to stringent cost control and high productivity levels.

The business model for Kroondal Platinum Mine (KPM) is one where as many of its operational functions are outsourced as possible. The underground mining operations are undertaken by Murray & Roberts Cementation, who as part of its value proposition offers a specialist underground contracting mining service to the mining industry.

Kroondal Platinum Mine, as part of BEE compliant Aquarius Platinum, has previously entered into strategic alliances with Impala Platinum and Anglo Platinum. Most recently, Aquarius Platinum entered into a second “pool and share” arrangement (P&SA2) with Anglo Platinum. The P&SA2, subject to the Development Plan being approved by the relevant company boards and Competitions Commission approval being granted, is targeted to come into effect in September 2005 and will see an adjustment to the Kroondal PSA boundaries.

Dave Starley, general manager at Kroondal Platinum Mine, says this latest development is aimed at optimising the utilisation of contiguous available mining reserves for both Rustenburg Platinum Mines (RPM) and AQPSA.

Infrastructure and equipment

Kroondal is primarily an underground operation, with an open pit area that is slowly tailing off. The upper-group-2 (UG2) reef is an important PGM-bearing ore body with sub outcrops on the property and dips to the north at approximately 9 degrees. This ore body comprises two mineralised seams which are the main and the leader reefs. These reefs are separated by a pyroxenite zone of about a metre thick, commonly known as the parting or middling.

The full width of the UG2 reef is mined, resulting in a wide-reef operation averaging about 2.3 metre thick underground. Blasting control creates large waste rocks in the parting zone, and a large portion of these rocks are separated underground to improve the economics of the mining operation by supplying a higher grade product to surface.

“The practice of ‘wide-reef mining’ at Kroondal translates into an increased resource and improved safety with the competent hanging wall. Kroondal’s success can further be ascribed to the use of the latest technologies, the skills and expertise of the management team and the commitment of all employees which is required for an efficient contract mining operation,” Ken Matthysen, business unit manager for Murray & Roberts Cementation, responsible for Kroondal Platinum Mine says.

Mining method

The scope of the mining contract at Kroondal includes all underground mining activities. The service department activities which comprise survey, rock mechanics, geology and ventilation are all outsourced by KPM but report directly to Piet Burger, mine manager for Murray & Roberts Cementation at KPM.

Mining is still in its build-up phase and will reach a steady state at the beginning of 2006 which will continue until the end of its life. Currently Murray & Roberts Cementation employs 2032 people on the mine.

Murray & Roberts Cementation has been involved with the mine since inception and the underground mining contract started in 1999 with underground production was targeted at 80 000 reef tons from the first two decline shaft systems, Central and East. This has subsequently changed as the PSA has led to four shaft systems, Central, East, #3 Shaft and #4 Shaft. The total production tonnage is expected to reach in excess of 540 000 tons per month at steady state.

As part of the forward planning, vertical shafts will be sunk at Central and East to facilitate access for men and materials in the deeper sections. Ore will always be removed via the decline systems. Chairlifts are being installed and will be used for ease of access by personnel. The mine is from surface and will extend to a vertical depth of approximately 400 metres at the northern boundary with RPM at the Central and East Shaft areas. In the other sections further to the east to the vertical depth will be about 250 metres.

Blasting is done conventionally with normal ANFO with an initiation system of capped fuse and igniter cord.

“We do our loading and cleaning of the panels with load haul dumpers (LHDs). The production fleet currently comprises 80 LHDs and ten electro-hydraulic drill rigs with 14 utility vehicles to transport material underground,” Burger says. All equipment is maintained by Murray & Roberts Cementation.

Kroondal Platinum Mine has 48 km of strike and dip conveyor belt systems to facilitate the extraction of ore to surface. Optimum control is enhanced through an integrated underground communication system which incorporates telemetry, leaky feeder and SCADA; this, including the conveyor belt system and other permanent infrastructure, is supplied by KPM. Supervisors are able to track and monitor the whereabouts of underground mechanised equipment as well as the conveyor system in real time. This facilitates the measurement of the entire underground mining operation output.

Layout and management

The Central and East Shafts are now in the sub-decline phase with the ore reporting to underground bunker systems to facilitate the smooth, further transfer of ore to surface. #3 Shaft will have a decline system reporting directly to surface and, in order to maximise ore transport to surface, #4 Shaft will comprise a main decline plus three sub-declines. In addition to all the other development work for the PSA, work began on #4 Shaft with the first blast on May 05, 2005.

In order to achieve the best results considerable effort on the part of Murray & Roberts Cementation has gone into planning of management structures and infra-structure. The management team has been handpicked in terms of the required capacity and skill. Murray & Roberts Cementation trains all personnel at the training centre at Bentley Park. A satellite training centre has been established on site at Kroondal.

Mining and planning principles

Murray & Roberts Cementation has worked hard at making sure that all the basic mining principles are done correctly. Top of the list is safety and quality which is achieved through attention to the details of basic mining.

Production equipment is closely monitored to ensure the availability required to meet productivity targets. The fleet maintenance and management is basic but extremely sound and very cost effective.

“Most of what we achieve depends on our people. We believe that they are top-class. We have a skills development programme which we run through specialist organisations as well as some in-house courses,” Burger says.

“Our systems-driven approach to the contract has been developed over the last 18 months. We are extremely proud of our progress and our achievements at Kroondal Platinum Mines,” Matthysen says.

“Kroondal Platinum Mine is, to date, satisfied with the performance of Murray & Roberts Cementation, and with our close co-operative relationship the status quo is set to continue,” Dave Starley says.

“The secret of having a successful client/contractor relationship is the partnership that evolves with mutual understanding and respect from both sides,” he adds.