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» Junior diamond miner switches to SA

» JSE:DIAMONDCORP PLC:
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Crusher woes tie up Diamondcorp revenue
Allan Seccombe
Posted: Thu, 03 Jul 2008

[miningmx.com] -- DIAMONDCORP, the JSE and AIM-traded diamond producer, said its revenues had been negatively affected by a failure of its re-crusher system in dealing with tailings.

The single-asset company is treating tailings at the Lace kimberlite mine not far from De Beers’ Voorspoed diamond mine. Diamondcorp reckons its work to access the kimberlite through a newly built decline system as well as an existing vertical shaft is 14 months ahead of schedule.

Erratic electricity supply and bad weather have hampered Diamondcorp’s operations in the past and now it is having problems with the re-crusher circuit not performing to expectations, being unable to achieve a consistent crushed size.
currently investigating legal action
A new crusher for the re-crush circuit will be installed during the next three months as a stockpile of material to be put through the system grows daily.

“The company estimates that up to 30 percent of the diamonds and 40 per cent of the revenue in the tailings is contained in re-crush diamonds, so the failure of this circuit has had a significantly negative impact on revenues,” chairman Euan Worthington said in a statement.

“The Company is currently investigating legal action against the plant process designers to recover this loss,” he said.

The stockpile of treated tailings material awaiting re-crushing is now 200,000 tonnes and it is growing as 35% of run-of-mine tailings is delivered for re-crushing.

A number of new crushing systems are being tested and the existing cone crusher will be made a secondary crusher.

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Diamondcorp shares were up 2.1% at 72.5 pence in London. They were untraded in Johannesburg.

Diamondcorp has completed a 9km power line to feed power from the supply to the Voorspoed mine to Lace, providing a more reliable source of electricity from next week.

The tailings yielded 27,103 carats of diamonds in the first six months of the year, of which 70% were of gem quality. The average recovery was 6.1 carats per 100 tonnes (cpht). Once the re-crusher circuit is re-established, another 3 cpht will be recovered.

Diamondcorp sold 19,214 carats in the interim period, raising $1.163m or $61/carat. The non-gem stones are sold once a year.

Work on the decline is proceeding at a rate of 120 metres a month and the satellite kimberlite will be reached within three months and a 20,000 tonnes bulk sample from that pipe will be extracted from September.

The decline will continue towards the main kimberlite, which will be reached in the first quarter of 2009.

DiamondCorp will extract 1,000 tonnes of underground material a day as part of its bulk sample programme. At full production, the mine will produce 4,000 tonnes/day.