Posts Tagged Fritz Geophysics

Deep penetrating geophysical survey in Mexico

Posted by on Saturday, 4 June, 2011
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Canasil Resources Inc.  announces that results from the recently completed ZTEM airborne geophysical surveys have outlined encouraging targets at the Company’s 100% owned Salamandra and Victoria projects in Durango State, Mexico. The ZTEM geophysical surveys at both projects have highlighted well developed structures which are possible locations for structurally controlled mineralization. These areas exhibit complex electromagnetic and magnetic signatures, which have the characteristics associated with intrusive sources, and are coincident with prospective local geology and geochemical surface anomalies defined by prior surface mapping, sampling and drill programs. These combined features have defined large targets for further exploration. A summary of the results at each project is included below for reference.

Bahman Yamini, President of Canasil, commented: “We are very pleased to see clearly defined and prominent geophysical signatures from the ZTEM surveys at Salamandra and Victoria projects. These provide significant high potential targets for follow up at these two large projects, both strategically located close to the city of Durango in a highly prospective mineralized belt in Durango and Zacatecas States, Mexico, hosting major silver and base metal mines. We look forward to further exploration programs to advance these projects.”

Salamandra Project:

The recently completed ZTEM geophysical survey on the Salamandra Silver-Zinc project in Durango State, Mexico, has outlined a large complex area, measuring 2.5 km by 3.0 km, with low resistivity and flat magnetic response, interpreted to be an intrusive source. This is located east of and flanking the previously drilled Salamandra mineralized zone. The interpreted intrusive source is bounded by a north trending large regional fault on the east, and crosscut by several east–west fault zones. According to Frank Fritz, Canasil’s consulting geophysicist: “these are favourable locations for structurally controlled mineralization”.

Previous drilling on the western flank of the interpreted intrusive source intersected wide zones of calc-silicate skarn with disseminated silver-zinc mineralization, averaging 0.5% – 1.0% zinc and 5 g/t – 20 g/t silver, and  high-grade silver-zinc sulphide filled structurally controlled breccia zones grading up to 20% zinc and 300 g/t silver.

The interpreted intrusive source outlined by the ZTEM survey is alluvium covered and has not been drill tested. There is excellent potential in this area to outline disseminated mantle replacement or high-grade breccia associated silver, zinc and copper mineralization related to acid quartz porphyry intrusives, similar to the large San Martin mine of Grupo Mexico, located 80 km to the southeast. Follow up surface mapping, geochemical and ground geophysical surveys are planned to further explore this high potential target.

Victoria Project:

The deep penetrating ZTEM geophysical survey on the Victoria project, located 25 km northeast of the Salamandra project, has outlined a target similar to that seen at Salamandra. The ZTEM survey has outlined an area of complex low resistivity and low magnetic response measuring 2.0 km by 2.5 km, indicating a large intrusive source at depth. Numerous zones with small workings of oxidized sulphides with anomalous lead, zinc, gold, arsenic and antimony are observed at surface associated with silicified and skarn altered sediments and small intrusives located immediately north, east and west of the outlined geophysical target. Several strong northeast and east-west trending shear structures are present similar to the Salamandra project target.  The geophysical target outlined at the Victoria project has the potential to be a large massive sulphide skarn mantle mineralized system similar to the San Martin base metal mine of Grupo Mexico located 80 km to the southeast. A follow up program of geological mapping, rock and silt sampling and ground geophysics is planned.

The ZTEM airborne geophysical surveys were conducted by Geotech Ltd. The data was processed and provided by Geotech Ltd. The interpretations of the geophysical data were carried out by Frank Fritz, consulting geophysicist, and Gary Nordin, P. Geo., Director of Canasil and a qualified person under NI43-101. The surveys were flown with 10 km line length with a spacing of 200 metres. The Salamandra survey covered 617 line-kilometres over an area of approximately 120 square kilometers. The Victoria survey covered 680 line-kilometres over an area of approximately 130 square kilometers.

The Salamandra project is located 35 kilometres to the northeast of the city of Durango and covers 14,719 hectares, over 140 square kilometres. This large claim area is strategically located within the major silver-gold trend running through Durango and Zacatecas States, and is directly on trend with a number of important operating mines and recent discoveries. The project benefits from excellent access and infrastructure for mineral exploration and development. Prior geophysics and diamond drilling completed by Canasil has identified significant zinc-silver mineralization at Salamandra, with preliminary metallurgical tests showing high zinc and silver recoveries to clean concentrates. The project is located on the mineral-rich Fresnillo geologic trend, approximately 80 km northwest of the San Martin mine of Grupo Mexico, which is the largest underground zinc-copper-silver mining operation in Mexico, producing at approximately 6,000 tonnes per day.

The Victoria project covers a large prospective area of 60,000 hectares, 600 square kilometers, located 60 km northeast of the City of Durango and 25 km northeast of the Salamandra project. The project is centrally located on the same mineral rich trend, stretching from the northwest to the southeast through Durango and Zacatecas States, with excellent access and infrastructure. Initial reconnaissance, including geologic mapping and surface sampling by Canasil in the Victoria project area, has outlined prospective target zones, which were tested by the ZTEM survey. Located on a major mineralized trend, the very large project area is highly prospective for discovery of new mineralized systems.


Geophysics Details of Exploration at the Little Butte Gold/Copper Project in Arizona

Posted by on Saturday, 19 February, 2011

Tuffnell Ltd. Announces Geophysics Details of Phase II Exploration at the Little Butte Gold/Copper Project in Arizona Confirming Mineralized Structures averaging 400 feet in Width and at Least 3,000 Feet Long.

Tuffnell Ltd. announces gradient IP-resistivity survey details (Geophysics) of the Phase II Exploration program at the Little Butte Gold/Copper Project.

Mr. George Dory, Tuffnell’s CEO, is pleased to report that Tuffnell’s geophysical survey interpretation indicates the mineralized structures discovered to date are part of a major north-south strike-slip fault system that averages 400 feet in width and is at least 3,000 feet long. Additional north-south structures were identified to both the east and west.

A gradient IP-resistivity survey was conducted over a 3,600 by 3,600 feet area centered on drill hole LB-1010. A30 meter dipole spacing was used along east-west lines spaced 100 meters apart. The survey was completed by Zonge Engineering of Tucson, Arizona and interpreted by Frank Fritz, a respected geophysicist.

Mr. Fritz’s interpretation shows several north-south structures offset by east-northeasterly trending later faults. There are also two large resistivity lows and two associated smaller IP effect highs. By far the most impressive feature runs north-south through the middle and correlates well with the structure and mineralization found in the Company’s drilling. This resistivity high runs at least 3,000 feet to the north and averages 300-500 feet in width. Fritz interprets this feature as an altered structure. He interprets a steep easterly dip on the east side where an IP effect high also occurs. The IP effect high may be associated with sulfide mineralization at depth. A similar but weaker resistivity/IP effect anomaly occurs on the western boundary of the survey.

Fritz also interpreted several other north-south faults worth future follow-up.

Geology of the Little Butte Property

Basement rocks at Little Butte consist of Precambrian age granite, gneiss and to a lessor extent, schist. Tertiary age sediments and volcanics were deposited on the Precambrian rocks beginning with a basal conglomerate derived from the basement.

Above the conglomerate is a thick section of arkose-rich sediments. This section, which also contains siltstone, limestone and a few tuffaceous units is often calcareous. The arkosic portion of the section hosts the bulk of the copper-gold mineralization tested by Homestake.

Doming, caused by the inferred emplacement of a Tertiary age intrusive, has tilted older Tertiary sediments and erosion has exposed Precambrian basement rocks. This doming has a northwest elongation parallel to the regional bedding trend. Regionally, rocks dip southwest, but around the dome rocks dip off of the former high. The most prominent structures trend northwest, with northeast faults less conspicuous and north-south faults common but poorly defined. The northwest and northeast sets appear to be tensional features while the north-south set is strike slip in origin. The northwest set is dominant, probably younger than other trends and may be in part post-mineral. Rotation along half-graben faults is evident especially along northwest trending faults in the northeastern portion of the district. The north-south and northeast structure sets appear most mineralized.

Quartz-hematite-sulfide (oxidized) stockworks and sheeted vein structures are found within the granitic basement rocks over a 3,000 feet by 4,000 feet area. A recently completed study of stockwork veining within this area shows alteration and mineralization characteristic of the Grasberg mine in Indonesia. Early widespread intense potassic alteration is cut by hematite veins and then by quartz-sulfide veins. Grab samples used in the study and containing quartz-sulfide veins assayed as high as 1.05 oz/t (36 g/t) gold. The gold seen at surface could be leakage from a much larger mineralized cupola occurring above an intrusive body at depth.
When the veins discovered to date are plotted on the resistivity map a district scale structural interpretation soon emerges. The veins which strike N30-35W are formed by right lateral strike-slip movement. Dilational faults occur as a result of the strike-slip movement causing extension between the two major north-south boundary faults. The company now has a well defined target easily tested with additional drilling. Also of interest is Mr. Fritz’s belief there is a major dike under the central portion of the resistivity high. This dike may be the source of the mineralization and begs a deeper drill hole at some point in the Company’s exploration program.

The geophysical survey interpretation indicates the mineralized structures discovered to date are part of a major north-south strike-slip fault system that averages 400 feet in width and is at least 3,000 feet long. Additional north-south structures were identified to both the east and west and a similar but weaker second anomaly occurs along the western margin of the survey. The identification of the geophysical target associated with the mineralization defines a discrete target that can be easily drill tested.

A map showing the location of trenches and the current drilling program may be found shortly on the Tuffnell website. Assay results for drilling will be released as soon as all results have been interpreted.

After all results are in and interpreted from the current trenching and core drilling, a plan for further testing will be developed using all available data. This plan will undoubtedly include RC drill testing to the north of the IP anomaly overlying the LB-1010 zone and other anomalies found by the survey. Further core drilling may also be appropriate if the LB-1010 zone remains open along strike and at depth. Planning for a deep test of the Grasberg style copper/gold target will continue as the winter exploration program develops. Tuffnell is also in the process of planning its Phase 3 exploration program and believes Phase 3 to be a very important milestone for the company as results continue to be very exciting for the Company.

Copper-gold mineralization occurs as two basic types at Little Butte. High angle faults, shear zones, and stockworks (as mentioned above) contain copper/gold mineralization in the form of quartz-hematite-sulfide (oxidized) veinlets. This structure hosted mineralization was slightly tested by Tenneco whose stated target was actually flat lying detachment fault hosted gold. Scattered drilling in the granitic basement found several narrow intercepts of 0.01-0.08 oz/ton gold.

Secondly, copper/gold mineralization also occurs in arkose of Tertiary age just above the contact with Precambrian granite. A 1988-91 gold exploration program by Homestake found several ore grade drill intercepts (best hole contained 21 meters averaging 0.127 oz/ton) gold hosted by the arkose. Several other +0.04 oz/ton intercepts occur across the tested area. The mineralization is all oxide and appears to be heap leachable as shown by the few bottle roll tests done.


Renewal of IP data with Fritz Geophysics

Posted by on Sunday, 13 June, 2010

Candorado Operating Company Ltd. announces about a thorough review and interpretation of the induced polarization and resistivity geophysical survey, completed in 2007 on their Man-Prime Property. This work is being conducted by Fritz Geophysics of Boulder, Colorado. Final results are pending. The initial interpretation has allowed a much better understanding of the structures and mineralized zones at the Man-Prime Property which will assist in identifying drill targets and in determining orientation of holes in the drill program to begin shortly, once the geophysical interpretation is completed.

Drilling will test geophysical anomalies and copper-gold soil anomalies. Also tested will be of an area of copper mineralization exposed in a trench at the Prime Zone. This trench is part of a much larger copper soil anomaly. Rock chip sampling in 2008 from this trench returned an average of 8550 ppm copper (0.85%) over 20 metres.

Murphy Lake Property
At Murphy Lake CDO is continuing the installation of 80 km of cut lines in preparation for a reconnaissance induced polarization and resistivity geophysical survey to be carried out once the grid is complete. The area of the survey adjoins on the south the Southeast Zone of the Woodjam South Property. On the Woodjam Property similar surveys have been successful in defining mineralized zones.

Man-Prime geophysical survey http://www.candorado.com/i/pdf/Man-Prime-Geophysical-Survey.pdf