VANCOUVER, BRITISH COLUMBIA--(Marketwire - Nov 26, 2012) - Silvercorp Metals Inc. ("Silvercorp" or the "Company") (SVM.TO)(SVM) is pleased to report results of the underground infill diamond drilling program for vein S7-1 ("S7-1") which is the current main production vein at the SGX (Ying) mine ("SGX"), Ying Mining District, Henan Province, China.
Highlights of selected intercepts:
- Hole ZK7AS7-103 intercepted a zone averaging 9.22m true width, grading 445 g/t Ag, 11.56% Pb and 2.80% Zn at the 445m elevation, including a massive galena zone, 1.57m true width grading 1,496 g/t Ag, 39.12% Pb, and 9.31% Zn;
- Hole ZK9S7-123 intercepted a zone averaging 10.03m true width, grading 646 g/t Ag, 4,34% Pb and 1.32% Zn at the 477m elevation, including an interval 1.42m true width grading 2,056 g/t Ag, 0.88% Pb and 1.98% Zn, and a massive galena zone 1.32m true width grading 2,497 g/t Ag, 30.58% Pb, and 4.58% Zn;
- Cross cut tunnel CM101-S7-1-450-SYM-ECM intersected a zone 7.33m true width grading 681 g/t Ag, 2.20% Pb and 3.13% Zn at the 450m level, including an interval 1.30m true width, grading 3,137 g/t Ag, 0.14% Pb and 0.38% Zn, and;
- Hole ZK9S7-107 intercepted a zone averaging 4.40m true width, grading 378 g/t Ag, 6.87% Pb and 1.47% Zn at the 467 elevation, including a massive galena zone, 0.62m true width grading 1,236 g/t Ag, 40.10% Pb, and 6.23% Zn.
As recommended in the May 2012 NI 43-101 technical report prepared by AMC Consultants the cut-off grades in the mineral resource estimates for the Ying Mining District have been reduced (lowered to 150 grams per tonne ("g/t") silver equivalent ("AgEq") from 300 g/t AgEq at the SGX (Ying) mine, and 100 g/t AgEq from 150 g/t AgEq at HPG, LM and TLP mines). As a result, the more selective re-suing mining method, which follows narrow high grade sulfide (massive galena) zones, is gradually being phased out for the less selective, bulk shrinkage mining. This change will likely capture a greater proportion of the ore, lowering the cost of extraction per ounce, and increasing cost efficiency. To facilitate this change an intensive infill drilling program was initiated in July 2012, especially on S7-1 at the SGX mine to more clearly define the ore body boundary.
The infill drill program has systematically revealed the existence of alteration zones containing silver and low lead-zinc contents outside of higher grade silver-lead-zinc stringers (massive galena) within the vein structure of S7-1. One such example is cross-cut tunnel CM101-S7-1-450-SYM-ECM which cuts through S7-1 on the 450m level near Line 7+70 and intersected S7-1 averaging 7.33 metres ("m") true width, grading 681 g/t silver ("Ag"), 2.20% lead ("Pb"), 3.13% zinc ("Zn"). Channel samples SG0755 and SG0756 occur just outside the narrow high sulfide zone (sample SG0757) and contain high-grade silver (up to 6,514 g/t) but almost no visually identifiable lead and zinc sulfides (0.14% Pb and 0.25% Zn).
Through observations made during the mining process, ore body boundaries can no longer be visually identified by the occurrences of lead and zinc sulfide as practiced previously (since the elevated silver content occurring in alteration rocks do not contain visually identifiable galena) and as such need to be identified using assay results. Individual sample assays from different drill holes listed in Table 1 below show that high silver low lead and zinc intercepts exist in almost every drill hole. This renewed understanding of geology, alteration, and mineralization of S7-1 and other veins at the SGX mine introduces the need for denser infill drilling of 25m by 40m spacing (previously 80m by 100m) and may have a positive impact on the future resource estimates.
Previously, stopes were designed to use the more selective re-suing method to mine the high galena zones within the S7-1 structure. Denser infill drilling (15m by 20m) and cross cut tunnelling was completed for a mineralized block of S7-1 between the 490m to 450m levels and the exploration lines 7+40 to 9+20, resulting in a much wider ore body with separate high silver-lead-zinc and high silver zones. The average true width of the eight drill holes (ZK9S7-104, ZK9S7-107, ZK9S7-123, ZK9S7-111, ZK9S7-152, ZK9S7-153, ZK7AS7-150, and ZK07AS7-103) and two cross cut tunnels (CM101-450-S7-1-ECM3 and CM101-450-S7-1-ECM) of the block is 5.49m grading 357g/t Ag, 3.95% Pb, and 2.51% Zn. As a result of this dense infill drilling and cross cut tunnelling, a much wider ore body with lower grades was defined and therefore the shrinkage mining method will be used to mine the stopes.
Since August 1, 2012 (when the Company last reported exploration results for SGX), 5,966m of drilling in 33 drill holes has been completed for S7-1 using eight drill rigs. Assay results for 14 of the 20 holes intercepted significant high grade silver-lead-zinc mineralization with the results for the remaining holes pending. Currently, 33 underground and three surface drill rigs are completing infill drilling at the different mines in the Ying Mining District.
Table 1: Selected drill hole and cross cut tunnel assay results from the S7-1 vein at the SGX mine
|Drill Hole/ |
Cross Cut Tunnel
Drill cores are in NQ size. Drill core samples, limited by apparent mineralization contact or shear/alteration contact, were split into halves by saw cutting. The half cores are stored in the Company''s core shacks for future reference and checking with the remaining samples being shipped in security sealed bags to the Chengde Huakan 514 Geology and Minerals Testing and Research Institute in Chengde, China, 226km northeast of Beijing, an ISO 9000 certified analytical lab. The samples are dried and crushed to minus 1mm and then split to a 200-300g sub-sample which is further pulverized to minus 200 mesh. Two sub-samples are prepared from the pulverized sample; one is digested with aqua regia for gold analysis with AAS, and the other is digested with two-acids for analysis of silver, lead, zinc and copper.
Chip samples are collected along sample lines perpendicular to the mineralized vein structure in exploration tunnels. Spacing between sampling lines is typically 5m along strike. Both the mineralized vein and the altered wall rocks are cut with continuous chisel chipping. Sample length ranges from 0.2m to more than 1m, depending on the width of the mineralized vein and the mineralization type.
Chip samples are prepared and assayed with AAS at Silvercorp''s mine lab located at the mill complex in Luoning County, China. Samples are dried at 100° to 105° C in an oven and are then crushed and pulverized through three procedures: preliminary crushing, intermediate crushing, and final pulverizing. Sample splitting is conducted at each procedure. A 200g sample of minus 150 mesh (0.1 mm) is prepared for assay. A duplicate sample of minus 1mm is made and kept at the lab for archives. A 0.5g pulp sample is treated with two-acid digestion and assayed for silver, lead, zinc and copper with AAS at the lab.
A routine quality assurance and quality control procedure is adopted at each lab to monitor the analytical quality at the lab. Certified reference materials (CRM), pulp duplicates and blanks are inserted into each lab batch of samples. QA/QC data at the lab are attached to the assay certificates for each batch of samples.
The Company maintains a comprehensive quality assurance and quality control program to ensure best practices are effected for drill core sample preparation and analysis. Project geologists regularly insert CRM field duplicates and blanks to each batch of core samples to monitor the sample preparation and analysis procedures at the labs. The analytical quality of the labs is further evaluated with external checks by sending approximately 3% of the pulp samples to higher level labs to check for lab bias.
Data from both the Company''s and the labs'' QA/QC programs are timely reviewed and evaluated by project geologists.
Myles Gao, P. Geo., is the Qualified Person on the project as defined under National Instrument 43-101. He has verified the information and has reviewed and approved the contents of this news release.
Silvercorp is a low-cost silver-producing Canadian mining company with multiple mines in China which has paid a cash dividend since 2007. The Company is currently developing the GC project in southern China which it expects will become its next operating mine in early 2013. The Company''s vision is to deliver shareholder value by focusing on the acquisition of under developed small-scale projects with resource potential and self-fund the growth of those assets. For more information, please visit our website at www.silvercorp.ca.
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Certain of the statements and information in this press release constitute "forward-looking statements" within the meaning of the United States Private Securities Litigation Reform Act of 1995 and "forward-looking information" within the meaning of applicable Canadian provincial securities laws. Any statements or information that express or involve discussions with respect to predictions, expectations, beliefs, plans, projections, objectives, assumptions or future events or performance (often, but not always, using words or phrases such as "expects", "is expected", "anticipates", "believes", "plans", "projects", "estimates", "assumes", "intends", "strategies", "targets", "goals", "forecasts", "objectives", "budgets", "schedules", "potential" or variations thereof or stating that certain actions, events or results "may", "could", "would", "might" or "will" be taken, occur or be achieved, or the negative of any of these terms and similar expressions) are not statements of historical fact and may be forward-looking statements or information. Forward-looking statements or information relate to, among other things: the price of silver and other metals; the accuracy of mineral resource and mineral reserve estimates at the Company''s material properties; the sufficiency of the Company''s capital to finance the Company''s operations; estimates of the Company''s revenues and capital expenditures; estimated production from the Company''s mines in the Ying Mining Camp; timing of receipt of permits and regulatory approvals; availability of funds from production to finance the Company''s operations; and access to and availability of funding for future construction, use of proceeds from any financing and development of the Company''s properties.
Forward-looking statements or information are subject to a variety of known and unknown risks, uncertainties and other factors that could cause actual events or results to differ from those reflected in the forward-looking statements or information, including, without limitation, risks relating to: fluctuating commodity prices; calculation of resources, reserves and mineralization and precious and base metal recovery; interpretations and assumptions of mineral resource and mineral reserve estimates; exploration and development programs; feasibility and engineering reports; permits and licences; title to properties; First Nations title claims and rights; property interests; joint venture partners; acquisition of commercially mineable mineral rights; financing; recent market events and conditions; economic factors affecting the Company; timing, estimated amount, capital and operating expenditures and economic returns of future production; integration of future acquisitions into the Company''s existing operations; competition; operations and political conditions; regulatory environment in China and Canada; environmental risks; foreign exchange rate fluctuations; insurance; risks and hazards of mining operations; key personnel; conflicts of interest; dependence on management; internal control over financial reporting as per the requirements of the Sarbanes-Oxley Act; and bringing actions and enforcing judgments under U.S. securities laws.
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