Jul 18 2013
Dolly Varden Silver Corporation (“Dolly Varden” or the “Company) is pleased to announce that drilling has commenced on the Dolly Varden Property, located 26km by road from the tidewater at the village of Alice Arm, British Columbia.
This year’s 3,000+ meter drill Program has begun with four holes for a total of 754 meters completed to date on the historically mined Torbrit deposit. A discussion of the results from these drill holes will be forthcoming in a subsequent news release. The Program will test for the continuation of the existing high-grade silver mineralization as it proceeds northwest onto the Musketeer property, towards the Red Point alteration – feeder zone. See following links for cross section and area maps.
- DV Torbrit Target Area
- DV Torbrit Cross Section
The goal of the 2013 drill program is to:
- define a new silver resource estimate around the existing Torbrit workings, extending the known deposit to the northwest. The historic resource on the Dolly Varden Property, from the four known deposits, totals 14.5 million oz. Ag, of which 7.9 million oz. Ag has been outlined in the Torbrit deposit . See Website (http://dollyvardensilver.com/dolly-varden-project/661-2/)
- demonstrate that Torbrit is part of a much larger Volcanogenic Massive Sulphide (VMS) system that points to a potentially larger and more extensive silver and gold rich target, located just northwest of the Torbrit at the Red Point zone. The Red Point alteration – feeder zone is geologically analogous to the alteration – feeder zone Eskay Creek; and
- continue to gather geotechnical information that will improve the probability of finding an Eskay Creek type deposit at Red Point. Information taken from the 2013 program will increase our understanding of the geological setting, the controls to mineralization, and geometry of the Dolly Varden Torbrit (DVT) horizon.
The Company’s expectations for the program, given the nature of VMS type systems, is to encounter variable but increasing mineralization as drilling steps out northwest from Torbrit. Currently, the Company’s team projects the plunge direction of the DVT horizon, and the contained Torbrit deposit, to continue from the 300m elevation above sea level at Torbrit, to 300m below sea level and under the gold-silver mineralized Red Point zone. This projection is consistent with the geology and geophysics within the integrated 3D geologic model.
First Stage of Drill Program
The first stage of Dolly Varden’s 2013 diamond drill program will involve drill sections, spaced on 100 meter centers, to test a 500 meter down plunge by 100 meter wide section of the DVT horizon. This unit hosts the historical Torbrit, North Star and Dolly Varden deposits which have been now identified as being part of a larger VMS system. Part of the drill program will target a very thick and productive extension of the Torbrit deposit that historic Torbrit mine records show is a very impressive central portion of the Torbrit deposit where an approximately 60 meter thick section was mined at an average silver grade of 17 oz/ton (530 g/t).
Recently, 3D modeling incorporating all the previously acquired data show a moderate to shallow NNW plunge to the thickest and highest silver grades. The same assembled data show an un-mined silver-rich “cap” (hanging wall) to the mined-out core of the Torbrit deposit.
Geologic Evidence
Evidence that the Torbrit deposit is developed over a width of 100 meters is taken from information from historic stopes; from historic drill holes that returned up to a 158 foot interval (at 12.6 oz/ton silver), adjacent to a stoped out area; and from 2012 underground sampling that returned 7 to 8 oz/ton silver over widths of 56 to 77 meters (DV news release, February 8, 2013). Evidence from the mined out portions of Torbrit, show that the deposit ranged from 10 meters to 60 meters thick.
The Company has used an integrated geologic model which will be updated with the results from this year’s drilling results, combined with all prior data to model the controls on the geology, the mineralization, and geometry of this thick section of the deposit.
The DVT Horizon Explained
The Company has now conducted two generations of helicopter-borne geophysical surveys: in 2010, an AeroTEM II, magnetic and radiometric survey; and in 2012, a new ZTEM and Magnetic survey. Importantly, provisional 2D inversion of the Geotech ZTEM Resistivity data has mapped the response of the footwall strata of the Torbrit silver deposits and also given a reliable and consistent interpretation of the important Salmon River formation strata, which is the host stratigraphy of the Eskay Creek deposit. The Company’s assembled 3D data and the newly obtained 2D Resistivity modeling has been integrated into a powerful new 3D model of the exploration targets on the Property.
The DVT horizon is an extensive unit that has been mapped for a strike length of 1,500 meters, and has been previously encountered by diamond drilling for a distance of 600 meters down dip/plunge. The DVT horizon is a complex unit comprised of laminated chemical sediments, explosive breccia, sulphide debris, and replacement silver, lead, zinc mineralization. The DVT is also the unifying horizon that connects the three silver deposits, Dolly Varden, North Star, and Torbrit, located at the southeastern edge of the DVT horizon, with an interpreted VMS type feeder – alteration system further north at Red Point.
At present, the most likely explanation for high-grade silver accumulations along this horizon, is an extensional graben or half-graben bounding fault that served as both a footwall conduit for venting hydrothermal fluids and as an ocean floor scarp that formed a linear depression, where mineralization could accumulate, within favorable locations along the extensive DVT exhalite horizon.
The program is expected to provide additional information about the geometry and attitude of this portion of the deposit, which will aid in following the entire trend down plunge northwest towards Red Point.
Size potential of Torbrit
It is possible to estimate a potential target tonnage that could be achieved from this year’s work program, based on the dimensions listed. We anticipate that the 2013 program will add significant silver ounces to our resource inventory. The calculations shown below provide an indication of the range of tonnages of potentially well mineralized material that could be outlined. Grades will only be determined once the drill core is logged and analyzed.
- 500m X 100m X 10m X 3.0 SG = 1.5 million tonnes
- 500m X 100m X 15m X 3.0 SG = 2.25 million tonnes
- 500m X 100m X 20m X 3.0 SG = 3.0 million tonnes
The potential tonnages set forth above are conceptual in nature and there has been insufficient exploration to define a Mineral Resource. It is uncertain if further exploration will result in the target being delineated as a Mineral Resource.
Assumptions would have to be made about the consistency of the silver grades encountered over these volumes, but if grades similar to the historical results, and the 2012 underground sampling results are indicated, then the total number of ounces could increase rapidly. Further results will be released as assays are received in Q3 and Q4 2013.
The scientific and technical information in this release has been reviewed and approved by Ron Nichols, P.Eng., President and CEO, a Qualified Person under the terms of National Instrument 43-101.
Source: http://dollyvardensilver.com/