The Weepah property is a Mesothermal, high-grade gold exploration property in the highly productive Walker Lane Gold Belt, Nevada. The property has been explored and mined intermittently since 1902. Surrounded by growing resources such as Columbus Gold’s Eastside deposit and West Kirkland’s Hasbrouck deposit, it provides an exciting opportunity to discover new gold resources in a historically productive district.
Figure 1: Property location and surrounding deposits.
The property consists of 76 unpatented lode claims and one patented lode claim totaling 590ha. Valterra has the option to acquire a 100% interest in the property with staged cash/share payments of $1 million. The property is subject to a 3% net smelter royalty that can be reduced to 2% by Valterra for US$2.5 million.
Historical production of gold and minor silver from Weepah occurred from shallow underground mines and a small open pit during two separate time intervals. From 1935 to 1939, Weepah Nevada Mining Co. produced gold from 305,000 metric tonnes grading 5.8 g/t. From 1986 to 1987, Sunshine Mining Co. produced at various grades approximately 60,000 oz. of additional gold with accessory silver. Historic production figures are from several published and unpublished company reports; however, a qualified person has not done sufficient work to verify these grades and tonnages, and Valterra cautions that these historic production figures should not be relied upon.
The gold mineralization at Weepah occurs within two broad shear zones. The western shear zone was exploited by the small open pit and adjacent underground workings. The eastern shear zone was exploited by historic workings and was extended by recent drilling. The zones have been traced for several hundred meters along strike and variably down dip. Portions of the shear zones are exposed at surface or in workings and portions have been traced by widely spaced drill holes beneath shallow gravel cover, which is generally less than 10m to 30m thick. Vein textures and geochemistry suggest the mineralization is similar to many other mesothermal vein deposits along the western margin of North America.
Work conducted by Valterra earlier this year included data compilation, 3D modeling, and identification of drill targets. Confirmation sampling by Valterra in the open pit yielded results similar to those reported by others. Highlighted Valterra sampling includes:
- South Pit face - Chip-channel samples of up to 3m of 9.01 g/t Au and 7m of 5.67 g/t Au in two adjacent samples,
- North Pit face - Chip-channel samples of up to 8m of 3.50 g/t Au and 1.2m of 2.81 g/t Au in two adjacent samples, and
- Center of Pit – A float sample returned 16.2 g/t Au and 10.6 g/t Ag.
Historic data provided with the property includes various geophysical surveys, geological mapping, bedrock sampling, interpretation of satellite imagery, and 4300m in 24 Reverse Circulation (RC) drill holes. Based on historic drilling, CSAMT & magnetics, the two ~50m-wide mineralized structural zones have a combined strike potential of ~2,000m. Other advantages of the Property include excellent infrastructure, low topography, and minimal cultural and environmental concerns.
The Weepah Project lies on the south flank of the “Weepah Pluton”, a westward extension of the much larger Lone Mountain Pluton. Lone Mountain is a prominent mountain approximately nine miles west of Tonopah and lies within the “Walker Lane Belt”, a 100km wide zone of northwest-trending mountain ranges related to a right-lateral shear zone, east of the Sierra Nevada Mountains. Within the Walker Lane, more east-west trending structural trends are recognizable. These include Lone Mountain and the Weepah Hills. The transverse structural grain of such features is thought to be related to transform faulting where strike-slip faulting is accommodated by oblique structure.
The Silver Peak-Lone Mountain region is documented by regional mapping to represent a metamorphic-core complex where the Mesozoic-age plutons have domed the Cambrian and Precambrian rocks of the lower plate and exposed the sole structure. The upper plate of the detachment is constituted by Tertiary rocks and less intensely metamorphosed Paleozoic rocks separated by a décollement from the lower plate, amphibolite-grade metamorphic rocks of early Cambrian age. The movement along the detachment structure continues to present time.
Map units at the Weepah Project include highly deformed, amphibolite-facies, marbles and schists of Cambrian age. Metamorphism appears to have characteristics of both regional and contact types. Cambrian units have been intruded by various intrusions. The felsic intrusive rocks have been highly differentiated with phases of pegmatite and alaskite, which are cut by multi-stage, auriferous quartz veins.
The rocks in the project area are highly deformed. An early phase of folding resulted in open (?) folds with east-westerly trends. At least one later event has superposed folding with southeast-northwest trends. Regional mapping by Oldow et.al, 2010 indicates that these deformational events are D3 and D4 that two earlier events (D1and D2) are also evident in the lower plate rocks at Lone Mountain and in the Silver Peak Range. Thrust faults have resulted in stacking of slivers of the Cambrian rocks and may in part be controlling structures for mineralization. The previously mined Weepah open pit exploited a moderately dipping vein zone, up to more than 10m wide.
Figure 2: View of the north and south face of the Weepah pit with VQA sampling highlighted
2017 Targeting and Exploration Potential
The Weepah project has good potential for continued discovery of additional gold mineralization. Exploration may now be conducted more systematically since the land package is now consolidated.
Figure 3: Proposed 2017 exploration program to aggressively offset existing gold mineralization. (Proposed holes are in red highlighted with yellow).
Two known target zones have been partially tested with favorable drill results. Both the Weepah Vein zone and the Weepah East zone have untested potential. The Weepah Gold Vein zone is exposed in the south wall of the open pit and has been intersected 730 metres south in two drill holes. The vein has also been intersected 235 metres downdip by one drill hole. Additional drilling is needed to explore the Weepah Gold Vein structure. Weepah East has been partially defined by close-spaced drilling and trenching. This zone remains to be fully defined and one drill intercept 150 metres south of the close-spaced drilling appears to be an extension of the mineralized zone.
The company is planning an initial 2,250m drill program consisting of five fences along the two identified shear zones, with each fence consisting of three (3) drill holes each for a total of 15 holes. Additional sampling is also planned to identify other potential shear zones and zoning patterns that have been indicated by multi-element geochemistry from very limited surface sampling.