Exploration
A major focus for exploration at Henty will be to increase the reserve/resource potential and to optimise life of mine planning. In recent years the exploration focus moved away from attempting to identify new ore zones to expanding and delineating those already discovered.
Past exploration efforts were sporadic and often failed to follow up on identified targets when more prospective targets were subsequently found. For example, once the Mount Julia and Darwin orebody Zones were located, practically all exploration effort in the upper sections of the mine ceased. This has left several targets still to be tested.
Exploration at Henty will be focused in two key areas: peripheral zones, which have potential to incremental mine life extensions, and new systems, with potential to materially increase mine life and production.
1) Peripheral zones
Opportunities exist in exploring the periphery of known zones for narrow mining potential. Mineralisation not extracted by previous owners will be examined to determine the applicability and scale of narrow mining methods. The current development plan has been built around giving priority to targets that will be economically accessible from the existing mine workings.
The Tyndall zone of mineralisation, located near existing mine workings, remains open for further exploration. This zone of mineralisation was drilled by previous owners but remained undeveloped due to a focus on the extraction of higher grade mineralisation in deeper sections of the mine.
A further prospective target is the Canal Zone Extension, which sits to the south of the Darwin Zone. One old exploration hole drilled in the late 1990s, intersected rocks reminiscent of those rocks directly above the Darwin complex. Two long holes from underground, Z16549 and Z16569, both appear to have run into rocks reminiscent of those directly below the Darwin complex. Follow-up drilling for the Canal Zone Extension has been encouraging, with previous owners intersecting a new zone of strong alteration with similar composition to the main Henty deposit alteration. This new "B zone" is located in the previously less-prospective hangingwall stratigraphy above the Canal Zone.
2) New zones
Perhaps the greatest exploration opportunities lie in the search for en echelon lodes, or up-dip, down-dip extensions which may provide repeat-scale systems of similar size to the reserves already mined (See Figure below).
Analysis by regional experts and external consultants, engaged by previous owners, all indicate high potential for the presence of such additional lodes. The scale and orientation of the structures involved in Henty mineralisation, combined with the extent of untested prospective stratigraphy and the wide distribution of alteration around the property, all indicate high potential for en echelon deposits.
The two Henty mining leases and exploration lease comprise roughly 28 square kilometres of contiguous land holdings. These leases roughly straddle the north-north-east to south-south-west trend of the North Henty, South Henty and Great Lyell Faults. The ground along and in proximity to these faults is of considerable prospectivity, and the region as a whole is recognized as an area of great mineral potential.
Figure 1. Long Section showing potential en-echelon lode exploration targets.
Click here to view Henty Development Targets - March 2009 Presentation
Click here to view Henty Exploration Group Forum May 2009 Presentation
