Foskor Planning for the Next Seventy Years
Improved throughput and sustainable production are the drivers of a R1.2 billion(US$128 million) expansion project at Foskor’s pyroxenite mine in Phalaborwa, South Africa.
Founded in 1951, the Foskor Group focuses on the mining and beneficiation of phosphate rock (foskorite and pyroxenite), from which it produces phosphoric acid and phosphate-based granular fertilisers for the local and international market.
Its open-cast mine in Phalaborwa, South Africa’s Limpopo Province, yields 2.6 million tonnes per annum of phosphate rock concentrate from processing 26 million tonnes of ore per annum. Once crushed, ground, milled, concentrated and dried, most of the phosphate rock concentrate is railed to Foskor’s processing plant in Richards Bay, 800km away on the country’s east coast. Palabora Mining Company (featured in a recent issue) is Foskor Phalaborwa’s closest neighbour, situated just 3km away from the existing Foskor open pit in the mineral- and metal-rich Phalaborwa Igneous Complex.
Commissioned in 1953, Foskor has traditionally mined foskorite and pyroxenite in a 60:40 ratio. With the body of foskorite ore nearing depletion, Foskor appointed Bateman Africa to undertake a feasibility study for the construction of a new mine to increase its pyroxenite processing. The study also included remedial measures to enhance throughput on Foskor’s Extension 8 processing plant. Dubbed the Pyroxenite Expansion Project (PEP), the project was split into two separate phases known respectively as PEP 1 and PEP 2.
PEP Phase 1
With the most recent extension to the mine being Extension 8 in 1999, PEP Phase 1 represents the ninth extension to the Foskor mine. Approved by the Foskor Board in September 2007, Phase 1 involves the construction of a new open cast mine for the mining of pyroxenite ore, together with the installation of a new primary gyratory crusher and an above-surface system to move the ore from the new mine to the existing processing plant 5km away. This new ore source guarantees an ore source for at least the next seventy years. By increasing the proportion of pyroxenite mined, it will enable Foskor to maintain its existing phosphate rock concentrate output. The R567 million(US$72 million) project is due for completion in May 2010.
PEP Phase 2
Like Phase 1, Phase 2 is not geared towards expanding production output. Instead, it focuses on de-bottlenecking the existing Extension 8 plant to improve its throughput rate to meet its original design capacity. The R650 million(US$83 million) PEP Phase 2 project was approved by Foskor’s Board in September 2008 and is due for completion in March 2011.
When Extension 8 was conceptualised in the late 1990s, a dry milling process was selected over the wet (ball and rod) milling process used elsewhere at Foskor. The advantage of the dry milling process was that ore could be reduced from greater than 125 mm to less than 0.5 mm in one processing step – with obvious economic and environmental benefits. However, as the Project Executive Mr Anton Nienaber explains, “Due to a combination of process design and equipment underperformance factors, the Extension 8 plant has never performed at design capacity for any extended period. Various process modifications have been attempted to rectify the performance and reliability shortcomings but none have been totally successful to date.”
“Foskor has therefore decided to de-bottleneck the Extension 8 plant by adding a separate, parallel tertiary crushing circuit to crush the ore from 125 mm down to 16 mm, and added a wet milling section (used elsewhere in the Foskor plant) to reduce the ore particles’ size from about 16 mm to less than 0.5 mm. After wet milling, the ore is re-introduced to the Extension 8 process at the flotation conditioners, together with the dry circuit ore. The combination of the two streams ensures that the flotation plant is fully utilised and that Extension 8 is able to perform at design output levels,” explains Nienaber.
Progress to Date
At the end of March, Phase 1 was 91percent complete, with only one month’s delay. At the same time, Phase 2 was two months ahead of schedule and already 71percent complete. Both phases are within budget – a significant achievement, given the complexity of both contracts. As Nienaber points out, the implementation approval of Phase 1 came at the height of the economic boom in South Africa, which meant that staff and technical consultants were in short supply and the project had to be managed in-house. Despite the challenges of managing such a large project internally, the project has been very successful so far, says Nienaber.
For Phase 2, Bateman Africa was appointed as the Engineering, Procurement and Construction Management (EPCM) contractor. According to Bateman Africa’s Mr David Norval, who headed the Foskor feasibility study and the Phase 2 contract, cost management and heat stress have been the two most significant challenges of the project to date. Apart from its successful management of the budget and programme, the contractor is proud to have achieved 250,000 injury-free man hours to date. “To encourage this,” explains Norval, “We select and reward a ‘Star Section’ each month which has performed the best in terms of safety, environmental preservation (e.g. clean site), quality and time management.”
As a major contributor towards the agricultural sector in South Africa and abroad, particularly in India, Foskor is making sure that it continues to support food security well into the future.
Project Team PEP Phase 1
- Lead consultants: Multi Optima Engineering Consultants
- Civil contractors: Murray & Roberts – main civil contractor, Remiro Construction, Ilanga Construction
- Mechanical & structural steel installation suppliers: SMEI, Utility Services, Kenco Engineering, Gage Specialists, Gears Technologies, Palasteel P&L Engineering
- Equipment Suppliers: IMS Engineering – crusher, Micropul – dust extraction & pressurisation units, Lockers Engineering – feeders, Demag – portal crane
- Instrumentation suppliers: Iritron – instrumentation supply and installation contractor
- Electrical suppliers: MJM Electrical, ABB Electrical
- Bulk Earthworks Contractor: LA Crushers
Project Team PEP Phase 2
- EPCM Contractor: Bateman Africa
- Main civil contractor: WBHO
- Bulk Earthworks Contractor: LA Crushers
- Mechanical contractor: KENCO Engineering
- Electrical contractor: B&W Electrical MJM Electrical, Zest Power Generation – supplied generators
- Equipment Suppliers: Bateman Engineered Technologies – conveyors & thickener rake, FLS Minerals – mills, Joest – vibrating feeders and screen Slurry Pump Services – pumps, Osborn – crushers
