Golden Spec
The Golden Spec deposit lies less than 1km along strike to the west of the Blue Spec deposit and has a JORC resource of 35,000 oz Au @ 32.2g/t .
The Golden Spec deposit demonstrates the key Blue Spec Shear mineralisation style characteristics of very high gold grades which increase with depth, demonstrated continuity of mineralisation with depth and distinct metal association. The presence of the Golden Spec deposit along the Blue Spec Shear zone supports Northwest’s theory that the Blue Spec Shear has the potential to host multiple high-grade gold deposits.
History
The main shoot of the Golden Spec deposit was discovered in the early 1970’s and the western shoot was discovered in 1986. Mining at Golden Spec was undertaken from 1986 to 1991 to a depth of only 120m.
Gold production from the Golden Spec deposit suffered from the same factors which affected the Blue Spec deposit. In particular, poor upper level development and inadequate capitalization under previous owners.
Since acquiring majority control of the Blue Spec Shear Project, Northwest has devoted considerable efforts to collecting and digitizing all of the Golden Spec deposit’s historical development and drilling data. This work has enabled Northwest to successfully construct a detailed 3D geological model of the orebody, its development and probable extensions. Northwest’s sophisticated modeling has, for the first time, enabled the entire deposit to be interpreted over its full extent. enabling Northwest to predict with confidence significant extensions to the orebody below the lowest level of production.
Geology
The Golden Spec deposit comprises two main shoots with high-grade gold mineralization hosted in quartz veins that average approximately 1m to 2.5m in width over a combined strike exceeding 70m. The two shoots, main and western, exhibit strong near vertical plunge continuity. High grade gold mineralization is variously associated with the presence of stibnite (the sulphide form of the metal antimony).
Similar to the Blue Spec deposit, during production, both grade and widths of the ore bodies increased with depth. Head grade increased significantly from around 15g/t Au in the upper levels to around 22g/t Au at the lowest production levels. The current JORC resource has an undiluted grade of 32.2 g/t.
JORC resource
The undiluted JORC resource calculated from 120m vertical to 370m vertical depth is:
|
|
Tonnes |
Au g/t |
Sb % |
Au oz |
Sb t |
Au Eqv oz |
|
Indicated |
9,853 |
41.6 |
2.2 |
13,161 |
221 |
13,869 |
|
Inferred |
24,098 |
28.4 |
1.1 |
22,000 |
261 |
22,840 |
|
Total |
33,950 |
32.2 |
1.4 |
35,161 |
482 |
36,709 |
Current and Proposed Development
Northwest has successfully constructed a 3D geological model of the Golden Spec deposit in conjunction with the Blue Spec 3D model. The model has enabled Northwest to successfully target interpreted extensions of the Golden Spec deposit almost tripling the depth extensions of the deposit to around 330m vertical depth.
Northwest’s drilling has not only confirmed the continuation of these extensions but also confirmed the increasing gold grades of the deposit with depth. Resource drilling has concentrated on defining the Golden Spec deposit’s depth extensions. The eastern and western strike extents of the shoots comprising the deposit are yet to be fully tested as is the zone between the main and western shoots.
Development of the Golden Spec deposit could be undertaken in conjunction with the development of the Blue Spec deposit, thereby reducing the capital expenditure which would otherwise be required for a stand alone mine.
In 2007, Northwest will assess near deposit shoot potential to increase the size of the existing resource to enable the deposit to be considered for underground operations. Golden Spec has the potential to be a valuable additional ore source for the Blue Spec Shear Project.
Page last updated: 29.01.2007
