South African company, Dowding Reynard and Associates (DRA), completed construction work on the 233,000t a month Marula PGM concentrator at the end of 2003 and finalised hot commissioning of the plant at the end of March 2004. The project was completed on time, below budget and with an excellent safety record.
Marula Platinum, situated on the Eastern limb of South Africa¡¯s platinum-rich Bushveld Complex is owned by Impala Platinum (80%), Mmakau Mining (10%) and other empowerment partners (10%). The name Marula is taken from one of the country¡¯s most famous and historically valued trees. Rich in folklore, there is hardly a part of the tree that is unused by the indigenous inhabitants.
The plant and infrastructure project undertaken for the Marula platinum mine was, in terms of value and size, the biggest PGM related contract undertaken by DRA to date. The company has undertaken numerous PGM related projects and in 2002 alone built six platinum concentrator plants.
Hot commissioning of the Marula plant began in January 2004, and by the end of February 60,000t of ore had been fed through the DMS plant with 45,000t of ore, milled. This commissioning was done using low-grade ROM ore, to save the mine¡¯s 400,000t high-grade stockpile until after the commissioning phase was complete. During the cold commissioning phase in November 2003 some 3,000t of waste from one of the shafts was put through the mills to test as much of the plant¡¯s operation as possible prior to hot commissioning. This initial run bypassed the DMS stage of the circuit and no reagents were used.
When in full production the Marula plant will treat 233,000t of ore a month. While the process technology used is conventional and standard for the PGM sector, a specific feature of the concentrator is its large DMS plant which eliminates a substantial amount of waste prior to the milling, flotation, thickening, tailings disposal, product dewatering and concentrate load out. The dense media separation phase increases the grade at which material passes through the mill from 3.5g/t to 4.66g/t.
The first load of concentrate was sent to the smelter in February 2004. Marula expects to produce 16,000oz of platinum in concentrate during Impala¡¯s current financial year with an eventual target of 100,000oz of platinum a year from January 2006.
The Marula plant and its layout have been designed so that it is possible to add a second module, increasing capacity to 400,000t a month should Impala and its partners wish to implement a phase II expansion in the future.
At the start of the project the Marula team appointed a group known as Teba to source local labour. This system worked well and Teba was able to liaise with local communities, which are varied and involve about six different groups. All contractors on the project were obliged to use as much local labour as possible. A knock-on effect of the project has been an improvement in the community¡¯s infrastructure, which includes a new road and the construction of a new school.
Dowding Reynard and Associates (DRA) specialises in providing technologically advanced mineral processing plants and engineering services and undertakes all aspects of projects from initial testing and piloting to final commissioning, plant extensions, upgrades and operation. During 2002 the company established itself as a world leader in the design and production of platinum plant.