Norseman Gold operates Australia's longest continuously running gold mining operation, having produced over 5.5 million ounces of gold over a period of more than 65 years from its Norseman field located 725km east of Perth, Western Australia.
Key projects
Exploration potential
Very good exploration potential has been identified both along strike and at depth of the existing mines and there are advanced targets located close to infrastructure that have the potential to become future ore sources.
The Company’s exploration programme is focused on the Main Field orebodies and the Harlequin orebodies, while at the same time undertaking resource drilling on development projects such as Harlequin South, Scotia Underground and North Royal to add overall mine life. In addition, a regional exploration programme will be undertaken to generate new targets and find new ore sources to add to the mine life.
The HV1 Reef has been the major source of gold from the Harlequin decline with over 300,000 ounces produced. Recent geological review and re-interpretation has highlighted a fault-offset structure and indicates that the down dip extension of this major reef has not been adequately tested. A drilling programme completed in December 2005 and February 2006 attempted to test this possible offset, and drilling results were very encouraging with results including:
- HD1516 -1.0m at 35.6g/t gold.
- HD1518 - 0.8m at 122g/t gold.
- HD1519 -0.45m at 40.8g/t gold.
- HD1520 - 0.48m at 257g/t gold.
Development of this area in recent months indicates that these results relate to the HV1 East structure, and that the HV1 repetition remains poorly tested.
Exploration drilling has also been targeted at the northern and up-dip extension of the HV1 East Reef in an effort to define an extension of a high grade stope. Significant results include 0.5m at 75.4g/t gold in HD1618.
Diamond drilling targeted the HV1 Reef down dip of the previous development. The drilling was unsuccessful in intersecting the HV1 Reef, however significant intersections associated with the extension of the HV1 East include 4.7m at 50.8g/t gold in HD1585B. This intersection is located outside of the current reserve boundary.
The Redfin Reef area is a very complex geological portion of the mine. High grade ore is currently mined from the Redfin Reef by long hole and airleg stoping methods. Exploration drilling has targeted the extensions to this system outside of the current defined Ore Reserve boundaries. Significant results returned include:
- HD1510 -1.41m at 26.9g/t gold.
- HD1513- 2.86m at 35.9g/t gold.
- HD1509 -0.71m at 11.4g/t gold.
- HD1540 -1.38m at 17.4g/t gold.
- HD1547 -0.77m at 29.4g/t gold.
Exploration drilling has highlighted a significant extension to the Marlin Reef, which has the potential to significant increase the resource base. Significant assay results returned to date include:
- HD1641 - 0.69m at 59.7g/t gold.
- HD1581 - 0.70m at 13.8g/t gold.
- HD1642 - 1.17m at 12.1g/t gold.
The Main Fields region encompasses the major historic reef systems of Crown, Mararoa and Norseman and extends over a strike length of 10 km. Gold production is currently sourced from the Bullen decline that provides access to the Bullen ore bodies, the recently developed St Patricks and Norseman ore bodies and the historic Mararoa workings. This area is a major focus for recent exploration, the success of which has highlighted the potential to increase production from this part of the field. The aim of exploration drilling is to identify new areas that may develop into production centres in the short term, and to complete drill testing of the Mararoa reef with the aim of identifying a new long-term production source.
There is good potential to extend the current Ore Reserves based on mining and drilling information currently outside of the defined boundaries. Mining of the St Patricks and Norseman ore bodies commenced in November 2005, with the Norseman reef performing beyond expectations, and the St Patricks Reef performing to expectations. These ore bodies currently remain open down dip and plunge, with limited definition drilling completed.
The Mararoa Reef is a major north-south striking, east dipping quartz reef with historic production exceeding 1 million ounces gold. Mining of this lode has re-commenced.
The development of the St Patricks ore body via the historic Mararoa workings provides a new opportunity to complete this exploration drilling in areas of the reef where mining was completed in the early 1950s and no previous modern exploration has been completed.
Highlights from the drilling completed on the Mararoa include:
- BN385 - 0.6m at 105g/t gold.
- BN326 - 0.4m at 93g/t gold.
- BN321 -1.75m at 8.9g/t gold.
- BN327 - 0.43m at 16.1g/t gold.
These results are very significant and indicate the potential of developing a new production centre on the Mararoa Reef.
Diamond drilling in the All Nations Area has identified the potential for a new mineralisation shoot to be hosted in a footwall reef approximately 40m vertically below the 16 Level. No previous development or exploration activity has occurred on this structure. Drilling completed to date has identified a minimum strike length of 80m with the zone open along strike and located approximately 70m in the footwall of the Mararoa structure. Significant results from this drilling include:
- BN414 - 0.6m at 14.8g/t gold.
- BN416 - 3.0m at 36.9g/t gold.
- BN402 - 0.2m at 40.2g/t gold.
These positive results require follow up definition drilling but demonstrate the potential of this region to host additional resource and reserves.
Development of the St Patricks and Norseman ore bodies is well advanced. To date all drilling targeting these reefs has been from surface, a depth of approximately 300m below surface. The defined ore shoots for the Norseman and St Patricks reef remain open at depth, and underground drilling is planned to test these extensions.
Four diamond drillholes have targeted the extension to the –317 level on the St Patricks Reef. The drillholes have returned encouraging intersections as demonstrated by results of for two of the holes reported below:
- BN430 -0.5m at 77.0g/t gold
- BN419 -0.35m at 45.2g/t gold
The extensive landholdings covering the major prospective units of the Norseman mineral field highlight the excellent opportunity for continued surface near mine and regional exploration to discover new gold mineralised systems within the project area. The current exploration programme has identified key areas of high priority where exploration is focused on defining new resources with the potential for mining in the near future.
The Company has defined several high priority targets at the Harlequin area and the proposed exploration programme for this area includes:
- Surface drilling to test for deep extensions of the HV1 and HV1 East structures.
- Drilling to test for extensions of the Harlequin South orebody.
- Drilling to test for parallel structures to the Harlequin South orebody.