Grenville Gold files Silveria NI 43-101 report on SEDAR
2007-08-28 16:02 ET - News Release
Mr. A. Paul Gill reports
GRENVILLE RECEIVES SILVERIA 43-101 REPORT, FOCUSES ON STARTING PRODUCTION
Grenville Gold Corp.'s National Instrument 43-101 report on the Silveria project has been filed on SEDAR.
"Grenville has already acted upon much of the advice of Minefill Services Inc. during the months leading up to production of this report," stated A. Paul Gill, president and chief executive officer. "We are moving forward on a number of key development items as can be seen from a review of this year's news releases."
The report's focus is to clearly outline the historical production of the immediate area, the project scope and objectives of the company in the short, medium and long range. The executive summary is reproduced below.
Executive summary of the Silveria project
Grenville Gold is engaged in the consolidation, appraisal and development of the Silveria project area, which comprises one of three mineral properties in Peru held by the company's Peruvian subsidiary, Inversiones Minera Alexander SAC. The concessions that comprise the project area are wholly owned by the subsidiary and the subsidiary acts as the company's agent regarding its current agreements with respect to its three Peruvian mineral properties. The company holds 90 per cent of the issued and outstanding shares of the subsidiary. The remaining 10 per cent is held by Minera Prospex SA, a Peruvian company that is jointly owned by L. de Melt, director and chairman of the company, and A.E. Ernesto Viduarre Otayza.
The project area is about 80 kilometres west-northwest of Lima, the capital of Peru. In July, 2007, it comprised 2,797.16 hectares in 224 concessions that cover four historical mining areas (Germania, Millotingo, Pacococha and Silveria). The Germania and Silveria operations were integrated with Pacococha mine at some unknown date or dates in their production histories. The Millotingo and Pacococha mines closed in 1992, due to a combination of weak metal prices and local terrorist activity by Shining Path.
It is anticipated that additional concessions, both within and around the main project area, will in future be purchased by the company, through the subsidiary. Concessions within the main project area are required to consolidate the company's control over the project area. The extensively mineralized nature of the main project area, as well as the presence of significant adjacent properties with similar mineralization and geological characteristics, emphasizes the potential future value of concessions acquired around the main project area. It is anticipated that the company will issue news releases in relation to additional concession purchases, as and when it is appropriate to do so.
Mineralization
Numerous underground mine workings exist across the project area, which workings are marked by the presence of drift portals and related rock dumps. The exploited mineralization is contained within vein deposits of the epithermal quartz-adularia, low sulphidation type. Broad alteration zones are also apparent. There are approximately 33 mineralized veins in the Pacococha mining area, seven mineralized veins at Germania-Silveria and two mineralized veins at Millotingo. Not all the veins appear to have been previously exploited. Field indications, as well as historical geology plans, suggest that additional mineralized veins might exist. The metals with economic potential include gold, silver, copper, lead and zinc (not listed in order of economic significance). Polymetallic mineralization, lack of gold and enriched arsenic-antimony in the Pacococha veins indicate that the upper levels of the epithermal system are eroded to below the boiling level, thereby exposing the base metal (plus silver) horizon. High-grade silver values, ore-grade gold values and low base metal values at Millotingo mine suggest it is higher in the epithermal system (in example where precious metals are enriched and base metals are depleted), possibly approaching the same or equivalent mineralogical environment as that found at the neighbouring Coricancha mine (that was recently reopened by Gold Hawk Resources Ltd. and which will soon reach design production capacity of 600 tonnes per day).
Exploration activity
The Silveria project is in the early phase of development, hence in the early phase of exploration activity. To date (July, 2007), the company has concentrated on consolidating the available database of historical Pacococha mine records, plans and sections into digital, three-dimensional (3-D) format. The results will be tied in with the digital results of surface topographic mapping to create a 3-D model in AutoCAD. Once the model is complete it will be used by the company to facilitate decisions concerning underground channel sampling programs, drilling programs and a scoping study. A similar 3-D modelling program is planned for the Millotingo mining area.
There is little evidence that any systematic exploration was undertaken across the project area, although historical geophysical plans show that an induced polarization (IP) survey was carried out across the northeast extension of the known vein area at Pacococha. There is, however, no backup report to substantiate the nature of the identified anomalies.
Opportunities
No formal, National Instrument 43-101-compliant mineral resource or reserve estimates exist for any of the four historical mining areas. However, the following potential mineral resources have been identified:
- Tailings dams adjacent to the Millotingo mill;
- Numerous, small- to medium-size mineralized surface rock dumps (not including dumps left by artisan miners for collection and sale);
- Unstoped vein areas in the underground mine workings, on existing production levels and in newly developed stoping areas both beyond and beneath the developed limits of the existing production levels;
- Various surface exploration targets.
Tailings dams
Consideration of the potential similarities of the Millotingo vein deposits with those found at Coricancha mine suggests that significant gold and silver grades might be present in the Millotingo tailings sited on a concession held by the company, through the subsidiary. The company is currently (July, 2007) planning a sampling program of the Millotingo mine tailings to assess the viability of heap leaching to recover the contained silver and gold.
Mineralized rock dumps
Numerous mineralized surface rock dumps of various sizes exist across the project area, especially in the Pacococha and Silveria mining areas. The presence of such material may be explained by the selective nature of vein drift development and stoping activity: individual veins were opened up/explored by means of vein drifting; stoping took place above only those sections of developed vein drift that were deemed to have intersected economic mineralization; and subeconomic material from the developed vein drifts was dumped as waste, either on surface or in mined-out stopes. A total of 34 grab samples of rock have been collected from dumps located down slope of accessible drift portals. The assay results show anomalous to low-grade gold values in all the Pacococha and Germania mine samples, but ore-grade gold values from Millotingo mine. Silver grades are consistently high in all the dump samples, with assays ranging from 3.50 grams per tonne (g/t) to 2,220 g/t Ag. Base metal values vary between 0.007 per cent and 3.90 per cent Cu, 0.01 per cent and 7.15 per cent Pb, and 0.07 per cent to 19.70 per cent Zn, with the lowest values reported for the Millotingo samples.
Current mine workings
Consideration of historical underground mining practice and reserve definition for Pacococha mine shows that potentially significant mineral resources might exist in the current mine workings, both in new stoping areas beyond the existing production levels and/or in unmined blocks between previously stoped areas. A central objective of compiling the 3-D AutoCAD model earlier outlined is to help strategize underground channel sampling and drilling programs aimed at identifying resource blocks that could be exploited in the existing workings. Once potential underground stoping blocks have been identified, the workings will be investigated to determine rehabilitation requirements and the practicalities of, and mining needs for, selective stoping.
Future mine workings
Consideration of the geology of the mineralized veins, as well as available historical stoping sections, suggests that possibly significant resources might exist below the current bottom production levels. Formal underground drilling programs are required to assess the vertical continuation of individual veins. Additional mine development will be required to facilitate underground drilling. Decline development (in preference to vertical shaft development) would eventually be required to access targeted stoping blocks.
Exploration potential
The results of a preliminary geological assessment suggest that there exists a potential to expand the available resources and define new resources through structured exploration programs that target potential extensions of known vein structures, potential new vein areas and areas of extensive but untouched alteration and disseminated mineralization.
Project development
The company has adopted a structured program of project development, due to the range of opportunities and the size of the overall project area. The following comments apply.
Short-term objectives
The company's main short-term objective is to establish positive project cash flow, at the earliest opportunity, by reprocessing available tailings. The secondary short-term objective is to produce ore from the existing underground workings. To this secondary end, once all the relevant data are in place, formal reserve statements, reserve depletion models, stoping schedules and cash flow models will be compiled. Initially at least, produced material might be sold direct to adjacent operations for processing. Integrated with these objectives will be detailed considerations of the cash flow potential of either selling or processing material from the numerous mineralized rock dumps.
Medium-term objectives
The company's main medium-term objective is to build a new (Pacococha) processing plant and thereby establish steady-state project cash flow. To this end, batch samples of average Pacococha mineralization will, at the appropriate time, be taken for purposes of metallurgical testing. The results will be used to design an appropriate metallurgical process, hence a new processing plant that will be sited at a location to be defined by Knight Piesold. Initial mill capacity will probably be limited to 350 tonnes per day, but designed so that future expansions to at least 500 tonnes per day can readily be achieved at minimum additional cost. The initial limit is to an extent fixed by Peruvian mining law that considers 350 tonnes per day to constitute a small mine operation, but allows capacity expansions of up to 50 per cent (in example to about 500 tonnes per day) without the need for additional government permitting. The provisional and preliminary estimate of an average on-site operating cost is $45 (U.S.) per tonne milled.
This compares with the cut-off value for economic mineralization of $56 (U.S.) per tonne that was applied in the mine's 1990 and 1991 reserve estimations, which cut-off value was probably the mine's average on-site operating cost per tonne milled.
Longer term objectives
Once steady-state mill feed production has been achieved, the company's longer term objective of exploring the potential for decline mining below the bottom levels of the existing underground workings will be considered through targeted underground sampling and drilling programs. Surface exploration potential will also be assessed, through structured exploration programs. It is at this time that further expansions to mill capacity (in example beyond 500 tonnes per day) might be contemplated.
Recommendations
MineFill supports fully the structured approach adopted by the company for the development of the Silveria project. Emphasis should in the short term continue to be placed on data consolidation to better identify opportunities for exploitation. Detailed research is recommended to definitively classify the Silveria mineral deposits so that a targeted approach to their exploitation, at least capital cost, may better be defined, especially as regards mineral processing requirements. In these regards, petrographic, spectroscopy, mineralogy, isotope geochemistry and fluid inclusion studies are recommended. Permitting issues should be reviewed to ensure any planned activities do not contravene existing Peruvian mining law. Environmental liabilities should be closely identified and scoped to ensure that penalties are not inadvertently incurred. The company should continue to actively pursue legally binding agreements with the local community and artisan miners as regards their future status on the company's property.
The technical information contained in this release has been reviewed by Jeffrey Reeder, PGeo, technical adviser for Grenville Gold and qualified person as defined in National Instrument 43-101.
In addition, Grenville will issue 300,000 options at 60 cents to certain directors, officers and consultants. The options will be exercisable for a five-year period and expire Aug. 27, 2012.
We seek Safe Harbor.
