Sign In
1 Mar 2010 07:00
|
Immediate release |
1 March 2010 |
Central Rand Gold Limited
("Central Rand Gold" or "CRG")
(Incorporated as a company with limited liability under the laws of Guernsey,
Company Number 45108)
(Incorporated as an external company with limited liability under the laws of
South Africa, registration number 2007/019223/10)
ISIN: GG00B24HM601
Share code on LSE: CRND
Share code on JSE: CRD
Trial Mining Update - Successful Stoping and CAF Pillar testing
Central Rand Gold ("CRG" or "the Company"), the gold mining company with assets in Southern Johannesburg, is pleased to announce an update on the progress of its Trial Mining operations. Key highlights include:
o All objectives of first trial stoping successfully met
o New geotechnical Cemented Aggregate Fill ("CAF") pillar has performed to specifications
o Stoping successfully commenced on either side of the trial CAF pillar
o Second trial stope panel blast on schedule for completion by end of March 2010
o CRG remains on track to complete trial mining by the end of 1Q 2010, where after Snowden Mining Industry Consultants ("Snowden") will complete a revised competent person's report on the project.
"The results of the initial stoping and CAF pillar installation have been very encouraging as they have proven that CRG has developed an economic, practical and viable geotechnical methodology through the use of CAF pillars. The final trial mining stage involves the mining of the second trial stope panel in early March to test and refine the ore extraction methodology. The conclusion of the trial mining will herald a significant milestone for the Company as it will, for the first time clearly define and physically prove the economic viability of its designed mining methodology." said Central Rand Gold's CEO, Johan du Toit.
Background
As indicated in CRG's Operational and Strategic Roadmap update on 22 January 2010,the company's objectives in 1Q 2010 are to :
·; Extract first stoping block in February
·; Complete Trial Mining and Metallurgical Testing on underground ore
o Trial mining exercise was designed to achieve three major objectives
§ To process ("ore") parcels from underground and surface activities as bulk samples to test gold grades and recoveries
§ To allow the conversion of Mineral Resources into Ore Reserves after confirming mining and metallurgical processes; and
§ To physically test mining and backfilling techniques.
·; Validate Snowden assumptions
·; Commence metallurgical plant upgrade to improve recoveries to 86%
·; Confirm technical feasibility and economic viability of the CRG Project
·; Issue a revised Snowden CPR based on the results of trial mining
·; Prepare for US$25 to US$35 million Q2 Capital Raising
Set out below is an update on the initial stoping and backfilling technique.
Geotechnical support
One of the key challenges for the Company's mining project has been to ensure that a stringent geotechnical methodology was developed. CRG used the services of Middindi Consulting, who have considerable experience in underground mining in South Africa, to assist in the design of this methodology, which was also independently reviewed by Snowden.
The basic geotechnical support design is as follows:
·; The Main Reef stope comprises a lateral 12m wide stope slot. The length of the stope slot will be determined by ground conditions and payability, but should not exceed 15m in length beween levels.
·; Between each main reef stope a 3m wide trench will be cut into the middling and Main Reef, which will then be filled using CAF, to create a cement pillar from footwall to hanging wall.
·; CAF consists of waste rock, water and cement which is mixed underground in a stockpile, and installed into the excavated trench using a loader. A bulkhead or stopper will be constructed below the trench. The CAF pillar will be allowed to cure for at least seven days.
·; After the Main Reef stope has been blasted a void will remain between the two CAF pillars that can be filled with backfilled waste
This geotechnical support design has been tested in full by the first trial mining blast, which took place on Wednesday, 24 February 2010. Photographs relating to the CAF pillar installation and stope blasting exercise can be viewed at www.centralrandgold.com.
Trial stoping
All set objectives have been successfully achieved through the first trial stoping blast. The main objectives of this trial stoping panel were as follows:
|
|
Objectives |
Result |
|
1 |
Would the stope blast on either side of the CAF pillar damage the integrity of cemented pillar?
|
Production drill holes were drilled at 35 degrees, 10m east and 10m west of the installed CAF pillar.
CAF pillar suffered no damage on either side due to blasting.
A 64mm hole was also drilled through the centre of the CAF pillar and examined by independent geotechnical consultants. No cavities were detected confirming successful continuity and installation of the CAF methodology. |
|
2 |
Would the stope drill and blast designed achieve the required fragmentation? |
Planned fragmentation achieved. |
|
3 |
Would stope blasting damage the hangingwall of the stope and cause significant rock failure?
|
Stope blasting resulted in minimal damage to the hangingwall. No significant rock failure was detected.
|
|
4 |
Would the blasted ore fall down a 35 degree slope (footwall) to the level below?
|
Encouragingly, an estimated 90% of the blasted material fell to the level below allowing easy extraction using a conventional loader. The remaining 10% was washed down to the reef drive below.
|
Further planned trial stoping
The second trial stope panel will test the performance of ore extraction over a 15m stope length between 12m spaced CAF pillars. This trial panel will test the resue stope mining method where the middling is mined first and then removed, followed by the mining of the Main Reef. This panel will be mined in early March and will determine the potential modifying dilution factors to be applied to the mine plan. A schematic of the mining method can be viewed at www.centralrandgold.com.
Pre-feasibility progress
Snowden has commenced revising the new operating and capital cost estimates to be applied to the mine plan based on real data determined during the trial mining phase.
Snowden is also reviewing the additional optical sorting test work currently being completed following the successful preliminary work concluded in December 2009. The additional test work has been carried out on higher grade Main Reef ore (6.5 g/t) in comparison to the previous test work which used a lower grade sample (2.4 g/t). The aim of these tests is to determine the efficiency of the optical sorter in upgrading the Main Reef ore by removing waste dilution or lower grade middling encountered during resue stoping.
Based on progress to date, CRG remains confident that it can achieve all the objectives within the stated timelines as communicated in January 2010.
For further information, please contact:
Central Rand Gold +27 (0) 11 551 4000
Johan du Toit / Patrick Malaza
Evolution Securities Limited +44 (0) 20 7071 4300
Simon Edwards / Chris Sim / Neil Elliot
Macquarie First South Advisers (Pty) Limited +27 (0) 11 583 2000
Thembeka Mgoduso / Annerie Britz / Melanie de Nysschen / Manisha Ramlakhan
Buchanan Communications +44 (0) 20 7466 5000
Bobby Morse / Katharine Sutton
Jenni Newman Public Relations (Pty) Limited +27 (0) 11 506 7300
Jenni Newman / Megann Outram
Follow the stocks
