Having reached its nameplate 160 000 (4E PGM) ozpa steady-state production target late in 2015, Northam Platinum’s Booysendal operation is already well underway with major organic growth expansion projects, valued at R4.8 billion, which will see its total output rise significantly over the next few years, general manager Willie Theron tells Laura Cornish.
Situated on the southern end of the Bushveld Complex Eastern Limb, the Booysendal property is significantly rich in PGM ounces, substantially more so than any of its neighbours (De Brochen, Mototolo and Two Rivers) with a 103.6 Moz resource, from the UG2 and Merensky reefs. This ultimately equates to the possibility of mining for more than 50 years.
Today Booysendal’s mainstay production is delivered from its UG2 North mine – a mechanised bord and pillar operation now comfortably delivering 160 000 ozpa of 4E PGM material from a ROM production rate of 187 500 tpm. As its name suggests, all material is generated from the UG2 reef alone from across a 3.8 km strike length, dipping at about 11°. Underground workings are accessed (uniquely) by a cluster of four declines (three on-reef and one in the footwall), and accessed via a reverse decline system.
At an average grade of about 2.9 g/t, Theron notes the necessity for a high volume operation. By comparison, Northam Platinum’s Western Limb-based Zondereinde deep level mine produces 300 000 ozpa at the same run of mine production rates.
Sitting pretty as platinum demand rises
While Northam Platinum is not expecting to see any significant spikes in the platinum price in the short to medium term, it does see demand for the precious metal outweighing supply in the long-term.
“Consequently, we believe the market is going to grow substantially in the long-term by at least a few million ounces and we are gearing ourselves to take advantage of that growth,” Theron states.
From a cost per unit perspective, the company is focused on driving costs down the cost curve to be amongst the fi rst cost quartile producers. “Our intent is not to become the biggest platinum producer but to maintain our position at the bottom of the cost curve (in terms of platinum mines) so that regardless of platinum price fluctuations we can sustain profitable production.”
Mechanisation delivers optimal mining value-add
Theron says the UG2 reef south of the Steelpoort fault on the Eastern Limb Bushveld Complex lends itself to mechanised mining because “it isn’t too narrow” – 180 cm (on average) compared to the typical UG2 package of 80 cm found on the Western Limb. Theron is a mechanised fan, and believes that in addition to being inherently safe, it is the key to successfully mining the property’s Merensky Reef as well. Because it is narrow and has lower grades, higher volumes are required to be cost effective. “Our ore body dictates this method. Mechanised mining also enables you to reduce labour, which compensates for high waste volumes, thereby enabling us to mine the narrow reef economically.” With a skills shortage in the area this approach in the longer term poses no threat to employment opportunities for the communities inhabiting the surrounding area. “The people we do employ will be better skilled and as such will be rewarded in terms of their wage allocations. The result is a mining operation of the future which eliminates many of the historic challenges conventional mines suffer from.”
Two major North mine expansion projects underway
Having so successfully brought the UG2 North mine on stream and into steady state production in the space of five years after development was first initiated in August 2011, a ‘great vision’ for larger-scale production was placed front and centre for Theron and his Booysendal team.
Mid-2015 saw the mine embark on a bulk sample to introduce a new Merensky mine, which in the space of a year was quickly completed. It has a 1.8 Moz resource and another 1.4 Moz in reserve. Having tested and refined its concentrator operations to ensure it can achieve similar grinds and recoveries when blending Merensky reef with UG2 reef, construction work to deliver the new underground mine ramped up significantly.
“We have already moved into a small mine phase at our North Merensky mine where we aspire to continue producing at a rate of around 25 000 tpm for the next three or four years which looks set to up the mine’s total production output to around 175 000 ozpa in 2017. Like its sister UG2 mine, the new operation also uses the mechanised bord and pillar mining method. “Delivering a Merensky mine has been a significant value-add to Booysendal’s overall performance – it gives us flexibility and better face lengths at very low costs. It is a true example of delivering a very effi cient capital expenditure project,” Theron outlines.
And already plans are being evaluated to ramp up the Merensky mine’s production further, to approximately 75 000 tpm – this would however require a volume handling upgrade to the Booysendal North mine concentrator.
Further to the new Merensky mining project, Theron notes that a deepening of the UG2 North mine is also underway (costing R270 million over three years) to add another two levels and 30 000 ozpa to the total production capacity with no additional fixed capital expenditure required. “This project will improve the utilisation of our underground infrastructure and allows for future deepening extensions as well. Because the dip belt will move onto the reef decline, it also removes the requirement for waste decline development.”
A key element to the deepening project is the delivery of a 3 000 t surge capacity underground silo that will connect the deeper, new section to the existing mine. Development of the silo started in May 2016 and physical construction is due for completion by July 2017.
Theron is excited about the results of both projects – which will see total PGM production increase to approximately 215 000 ozpa by 2018 at an average grade of about 3 g/t.
Booysendal South to double production
The new R4.2 billion Greenfields Booysendal South project, with three defined target areas situated adjacent to the North mine, will by 2022 effectively double the entire Booysendal operation’s production – to 475 000 ozpa.
“Once the necessary licences and permit applications have been awarded, Booysendal South will deliver 215 000 ozpa of 4E PGMs from a 235 000 tpm ROM production rate at a grade of between 2.8 and 2.9 g/t,” Theron explains. “It will comprise two UG2 bord and pillar mining modules, a small Merensky ‘swing production’ mine and shaft head infrastructure to support it. All the various modules will be accessed via a central portal complex which supports minimal environmental impacts and capital infrastructural requirements.”
The introduction of this new project is thanks entirely to Northam Platinum’s acquisition of the Everest assets from Aquarius Platinum South Africa in June 2015 which included most importantly a 250 000 tpm concentrator (currently on care and maintenance) and ancillary infrastructure including water and power supply and a tailings storage facility. “We will use the plant to process Booysendal South’s tonnages,” Theron notes. “Without this plant, the project would not have been feasible.”
To date the construction of the boxcut and access road has already started and temporary power and water necessary for construction completed. In March 2017 Booysendal North mine’s mining contractor Murray & Roberts Cementation will start the development of ventilation adits and the decline barrel development as well.
One of the project’s unique features will be an aerial rope conveyor used to transport the ore 4.7 km from the central mine to the plant – necessary because of extreme undulating typography.
There is in fact a 570 m diff erence in height between the two points and as such, Theron says this is the only viable materials handling option. The Ropecon system, as it is known, will be supplied by Austrian ropeway engineering company Doppelmayr Transport Technology, which is currently working on the engineering and design. “This is a first for Southern Africa and shows our position to pioneer new technologies in order to deliver operationally viable projects,” Theron highlights.
The conveyor will be ready for commissioning mid-2018. “At this point we will look to restart the South mine concentrator with the stockpiled material from the initial development and ledging done.”
Once completed, the entire Booysendal property will undeniably be Northam Platinum’s flagship mechanised operation and contribute significantly to total production in combination with its Zondereinde flagship conventional deep operation.
And while the expansion projects underway are enough to keep the Booysendal teams busy for the next few years, Theron notes there is even greater potential across the licence area to expand further, which is and will only be constrained by plant capacity. MRA