ERPM Gold Mine

 mine, production, mine shaft

The ERPM Mine was originally owned by Sir George Farrar and is the culmination of several old gold mines that were consolidated over the last 100 years.

This mine is now operated by DRDGold and consists of underground mining operation, retreatment of old tailings or slimes, and a gold plant, and produces around 80,000 ounces of gold a year. The mine was originally established in 1896 and was one of the deepest mines in the world at 3585 metres deep. East Rand Proprietary Mines (ERPM) is an underground mining operation which was established well over 100 years ago on the Witwatersrand Basin, 25 kilometres to the east of Johannesburg. Situated near the town of Boksburg, the mine was purchased in October 2002 by Crown Gold Recoveries (CGR). ERPM is now a wholly owned subsidiary of DRDGOLD SA.

Gold production totalled 79 479 ounces in the year to 30 June 2008.

Underground mining activities take place in the Far East Vertical (FEV) Shaft lease area while the infrastructure of the South East Vertical (SEV) Shaft is being maintained for hoisting and pumping as well as for accessing mining in remnant areas. The Main Reef formation is mined at depths of up to 3 200 metres beneath the surface. The plugging programme – the construction of underground dams to prevent rising water in the Central Witwatersrand Basin from flowing into the remaining production areas – was completed at FEV shaft and is 95% complete at SEV. The programme is partially funded by the government. The headgear of Hercules Shaft was demolished in September 2005.

The mine also produces gold from its Cason Dump surface re-treatment operation. Some 300 000 tonnes of underground ore are processed through the ERPM plant a year, while 1.9 million tonnes of surface materials are process through Crown’s Knights plant.
Growth projects

Early in 2006 DRDGOLD SA was granted prospecting rights under South Africa’s new minerals legislation in respect of the Sallies lease area adjacent to ERPM which is now known as ERPM Extension. A four-year exploration drilling programme is under way.

A concept study to determine how best to access the ERPM Extension 1 orebody was completed in the last quarter of FY08. This favours the development of a new ‘pay-as-you-go’ decline that circumvents the existing decline and uses technology that is proven to be both safer and more reliable. A feasibility study has been approved and is scheduled for completion by the end of 2008.

Once a mining right has been granted for Extension 1, it will allow the Composite Reef payshoot currently being mined on ERPM to be followed across the existing mine boundary. With mineral resources of 7.8 million ounces at 8.35g/t, this project has the potential to extend the life of mine from nine to more than 20 years.

Beyond the Sallies area (ERPM Extension 2), application has been made to extend the prospecting area into the 5 500ha Rooikraal/Withok area where independent consultants (Camden Geoserve and Minxcon) have estimated an inferred resource of 28.6Mt grading 9.06 g/t, a total of 8.3Moz. Should drilling confirm initial estimates, a due diligence exercise will be carried out which could culminate in a deep-level mine with a life of more than 15 years.

At the end of June 2008, ERPM employed 1 900 people including contractors.

Following the death of two employees overcome by carbon dioxide at the SWV Shaft on 19 September 2008, underground pumping at ERPM had to be discontinued. This led to the suspension of underground drilling and blasting on 31 October 2008. A process is in place to try to find an economic solution to the problem but with no success thus far. Consultations are being held with union representatives to determine the future of the mine’s workforce.

Surface operations at ERPM continue.

ERPM is situated on the Witwatersrand Basin near the town of Boksburg, 25km to the east of Johannesburg. It was established as an underground mining operation more than 100 years ago. Underground mining was suspended in October 2008 following the cessation of the pumping of underground water for safety reasons.

ERPM continues as a surface retreatment operation. It holds 65% of ErgoGold through the contribution of its Elsburg Tailings Complex. ERPM’s wholly owned Cason surface retreatment operation was incorporated into Crown during the fourth quarter of FY2010. Crown processes surface material from Cason through its Knights plant.

Early in 2006 DRDGOLD SA was granted prospecting rights under South Africa’s new minerals legislation in respect of the Sallies lease area adjacent to ERPM which is now known as ERPM Extension. A four-year exploration drilling programme is under way.

A concept study to determine how best to access the ERPM Extension 1 orebody was completed in the last quarter of FY08. This favours the development of a new ‘pay-as-you-go’ decline that circumvents the existing decline and uses technology that is proven to be both safer and more reliable. A feasibility study has been approved and is scheduled for completion by the end of 2008.

Once a mining right has been granted for Extension 1, it will allow the Composite Reef payshoot currently being mined on ERPM to be followed across the existing mine boundary. With mineral resources of 7.8 million ounces at 8.35g/t, this project has the potential to extend the life of mine from nine to more than 20 years.

Beyond the Sallies area (ERPM Extension 2), application has been made to extend the prospecting area into the 5 500ha Rooikraal/Withok area where independent consultants (Camden Geoserve and Minxcon) have estimated an inferred resource of 28.6Mt grading 9.06 g/t, a total of 8.3Moz. Should drilling confirm initial estimates, a due diligence exercise will be carried out which could culminate in a deep-level mine with a life of more than 15 years.

Reference for information:
www.drd.co.za/bus/ops_sa_er.asp
www.drd.co.za/b/erpm.asp
www.drd.co.za/b/crown.asp
www.saimm.co.za/Journal/v103n02p087.pdf
www.mwebfinance.com/Markets/Technical-Analysis/DRDGold-...
www.drd.co.za/im/files/fs/ERPM_fs_mar07.pdf


ERPM extension:
www.miningweekly.com/article/underground-exploration-dr...

Boksburg Historical Association:
boksburghistorical.com/index_files/BHAdecjan2006.pdf
www.docstoc.com/docs/71502165/Hercules-Mining-Company--...