Historic Diamond Core DrillingEagle Picher S.A. de C.V. explored the Cuale District between 1950 and 1959. In 1958, a total of 322.4 meters in three surface diamond drill holes were drilled into the Socorredora orebody (Holes EP1, 3 and 4). These were followed by 845.5 meters drilled from underground to explore for the down-dip extension of La Prieta (Holes C1 to C5). There is no record of hole diameter size. Core recovery ranges from 90 to 50%. There are no maps showing the location of the holes, but the logs do refer to an old mine grid system.
In 1968 Compañia Azteca drilled two short diamond drill holes on the Valenciana prospect with negative results. Between 1970 and 1972, Industrias Peñoles drilled another 2 or 3 holes (Fernandez-Valle, 1984).
In 1972, Zimapan started drilling the Cuale VMS camp, and drilling continued through to 1989. Drilling records show that both underground and surface rigs were used. Underground rigs were mainly used to drill NX, BX and AX diameter diamond core. Surface rigs were used to drill NQ, BQ and AQ diameter core (both regular and thin wall). Core recovery was not logged for all of the holes, but where it is known it ranges from 40% to 98%, with 50% of the core having 74% recovery or better. The collar locations are referenced in mine co-ordinates, which appear similar to the UTM grid system. It is not known whether Zimapan was working in NAD 27, or NAD 83. Even taking into account possible datum shifts over the time period, historic maps that show topographic information do not correlate well to INEGI's current version of the topography which is registered in the ITRF92 datum. Overall error estimates on the locations of the old drill holes range from 10 to 90 meters laterally and from 1 to 40 meters in elevation. Collar locations are not marked in the field, and it is not always obvious if the older roads are drill access or roads built for other purposes.
In 2003, the author of this Report, the previous President of Zinco Mining Corp, Brian Verner Hall and Thomas Bissig found parts of Zimapan diamond drill holes 643, 578, 525, 524, 4N, 156, 632, 422, 611 and 618 in a core shed next to the Cuale mill. This group re-logged these holes according to the standards of McPhie et al., 1994. The core logs of the Company do not resemble core logs by Zimapan, either because the core was disturbed in storage or perhaps because the field of volcanology has changed significantly over recent decades. The core shed has since collapsed.
It is the author's opinion that historic assay data is perhaps 85% reliable, but the geological data may not be that helpful. The major sources of error in the data would be errors due to manual transcription of the data between laboratory certificates and the handwritten core logs, and errors in the Company's transcription of the same.
Reverse Circulation (RC) DrillingA construction crew was mobilized to Cuale 1 March 2008. A suitable area for the camp was located on the Company's El Maple concession by the old powder magazine near Patrocinio. The powder magazine itself was rebuilt to house the kitchen and two rooms. A brick office was constructed across from the kitchen. A third plywood building with two rooms was built south of the main camp. The drillers were housed in Peñoles' camp a few hundred meters away. A D6N tractor was mobilized to the Property 23 April 2008. By 1 May, the 48.5 kilometer long section of road between El Tuito and Patrocinio Camp was repaired and upgraded. Between 2 and 13 May, the tractor was on standby waiting for SEMARNAT to issue the work permit. Between 14 May and 11 June, the bulk of the site preparation and new access road construction was completed.
All drilling was conducted, utilizing a "Buggy-type" reverse circulation drill rig contracted from Layne de Mexico in Hermosillo, Sonora. Drilling was done with two shifts per day, ranging in length from 10.0 to 14 hours. The drill arrived at San Juan the afternoon of 2 June 2008, and drilling operations continued through to 3 July 2008. The morning of 10 June, heavy rains related to a tropical storm closed the road to San Juan. When the road was dry enough to move the drill on the morning of 12 June 2008, drilling operations resumed. Although the Project was affected by two more tropical cyclones, the drill had been moved to the more accessible area of Jesus Maria by 19 June 2008, and there were no more weather delays. Over the 30 day period, 4753.2 meters in 33 holes were completed.
About 50% of the drilling was conducted dry, with only air circulation. Water injection was utilized where ground conditions or the abundance of groundwater mandated the change. Drilling rates were about 82 meters per shift. This was rather lower than expected, and was due to the exceptional hardness of the rock. In fact, conventional RC hammers could not be used effectively at San Juan or Jesus Maria, and diamond hammers were ordered for the Project.
Rotating crews of 5 people were on the drill site 24 hours to log and X-ray the samples and manage the overall sample collection. When the holes were completed, they were capped with a 1 meter by 1 meter cement plug, and the collar information was inscribed into the cement. Hole locations and access roads were surveyed with a hand-held Garmin GPS76Sx with internal barometric altimeter and no base station correction. Errors on the GPS easting and northing can be as large as 30 meters, but are typically on the order of 5 meters. Elevation estimates were highly variable due to stormy weather conditions. The surveyed positions of the roads were compared to IKONOS satellite imagery of the Project area. The elevations were compared to NASA digital elevation models published in 2008. Errors on the overall X,Y,Z locations are still on the order of 5-10 meters. No down hole surveys were completed.
Summary of assay results for reverse-circulation drill holes ZIM1 to ZIM33. The true width of these RC intercepts is not known. About 13% of the RC drill holes are mineralized.
HQ Diamond Core DrillingA construction crew was mobilized to Cuale 17 February 2011 to upgrade and expand the Patrocinio campsite. Starting 28 February, Ing. Jose Ramon Martinez Aguilar made the field inspections required to apply for the drilling permit, and contact was made with the Ejido of Cuale. By 11 March, 2001, work started on repairing access roads and drill sites. On 20 March 2011, Energold Drilling of Guadalajara sent Pedro Campoy to do a field inspection to bid on the drilling contract. On 3 April 2011, the Ejido of Cuale granted written permission to Minera Croesus S.A. de C.V. to do exploration drilling on Ejido lands. By 13 April, Energold had not delivered a bid, and Major Drilling from Hermosillo was invited to review the project. Their representative arrived on site 21 April, and the bid was delivered 27 April. On 2 May 2011, the Informe Preventivo was filed. Authorization to drill was received 20 May under document number SGPARN.014.02.01.01.1056/11. Major Drilling started mobilizing the drilling equipment from Hermosillo on or about 20 May, and hole ZIM34 was collared 5 June 2011.
All drilling was conducted utilizing a Mancore 600 man-portable diamond drill rig contracted from Major Drilling de Mexico, S.A. de C.V., Hermosillo, Sonora. Drilling was done with two shifts per day, ranging in length from 10 to 14 hours. The drill arrived at Patrocinio 29 May, and was mobilized to San Juan 4 June. The drill contract was completed 21 July 2011. Over the 47 day period, 1534.8 meters in 14 holes were completed. Drilling rates averaged 16.3 meters per shift. This was 20% lower than expected. At Jesus Maria, the ground rock was hard and silicified, and the maximum depth penetration of the rig under these conditions was on the order of 150 m. A Reflex survey instrument was used to measure the orientation and the dip of the holes every 50 meters down-hole. When the holes were completed, they were capped with a 1 meter by 1 meter cement plug, and the collar information was inscribed into the cement. Hole locations and access roads were surveyed with a hand-held Trimble GeoXH 3.5G 6000 series GPS with no base station correction. Errors on the GPS easting and northing can be as large as 10 meters, but are typically on the order of 2 meters. Elevation estimates were highly variable with errors as large as 10 meters. The RC collars were mostly re-surveyed at this time as well.
Summary of assay results for HQ diamond drill holes ZIM34 to ZIM47. The true width of these intercepts is not always known. About 45% of the diamond drill core is mineralized.
Beatty E.C., 1899, Report on the Property of the Union de Cuale Company, State of Jalisco, Mexico. Compania Minera Peñoles Report.
Hall, B.V., and Gomez-Torres, P.P., 2000, Geology of the Kuroko-type massive sulfide deposits of the Cuale district, Jalisco state, Mexico: in Sherlock, R. and Logan, M.A.V. eds., VMS Deposits of Latin America: Geological Association of Canada, Mineral Deposits Division Special Publication No. 2, p. 141-161.
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