Copper Zone Discovered at Kaoko Copper Property, Namibia
TORONTO, ON – September 15, 2010 – INV Metals Inc. (“INV Metals” or “Company”) (TSX: INV) is pleased to announce the discovery of a copper-rich zone including intersections of 2.0% copper and 27 grams per tonne (g/t) silver over a thickness of 45 metres (m) and 2.8% copper and 49.1 g/t silver over a thickness of 27 m at the Okohongo target (“Okohongo”) located on the Kaoko property in northwestern Namibia.
Mr. Robert Bell, CEO, stated, “The discovery of a copper-rich zone on the Okohongo target confirms the Company’s belief that the Kaoko property has significant potential to host sedimentary copper deposits similar to those in the African and Kalahari Copperbelts. Success during our initial drill program at Okohongo is extremely encouraging and demonstrates the potential of the entire Kaoko property. The drilling intersected significant copper and silver values, with intersections grading up to 4.5% copper and 66.4 g/t silver and thicknesses up to 45 metres. The Okohongo mineralization drilled to-date is continuous over 500 m of strike length and is open along strike and at depth. The structural setting of the Okohongo mineralization indicates a potential target strike length of 7 kilometres”.
The Okohongo target is one of 19 known copper targets within the extensive Kaoko property. The regional area surrounding the Okohongo target contains numerous untested structures on the margin of a large domal structure that extends approximately 40 kilometres and includes the Epunguwe and Otjohorowara targets, which also have potential for significant copper-silver mineralization (see Figure 4). Previous drilling by Teck Resources Limited and its local subsidiaries (“Teck”) at the Epunguwe target, five kilometres north-northwest of Okohongo, intersected 21 m of 1.7% copper and 14.1 g/t silver and 7 m of 2.2% copper and 177.7 g/t silver. Twelve kilometres northwest of Okohongo, the Otjohorowara target area displays essentially a similar geological environment to that seen at Okohongo. Set forth in Table 1 below are selected highlights of the Company’s 2010 drill campaign at Okohongo.
Table 1: Highlights – Okohongo Drill Results
|Hole No.||From (m)||To (m)||Interval (m)||Copper %||Silver g/t||Section|
INV Metals is currently performing detailed mapping and geochemical surveys within the immediate Okohongo target area and plans to conduct follow-up drilling at Okohongo and detailed exploration along the extended 40 kilometre target area later this year. The Company is well funded with cash resources of approximately C$10.5 million as at June 30, 2010.
INV Metals entered into agreements with Teck which provide INV Metals the right to acquire an initial 50% interest in the large Kaoko property (approximately 8,000 km2) located in northwest Namibia (see INV Metals’ press release dated August 4, 2009).
INV Metals completed a 20 hole, 2,564 m reverse circulation drill program in July at the Okohongo target (see Figures 1 and 2). The drill program was initiated to follow up the preliminary hole TCD-016 drilled by Teck in 2007, which intersected 25.2 m of 1.9% copper and 32.3 g/t silver. Results of the 2010 drill program are listed below in Table 2. INV Metals’ drilling has intersected a north-south trending zone of copper-silver mineralization over 500 m of strike length and up to 400 m down-dip. The mineralization dips gently eastward at 20 degrees. The copper zone appears to be open to the south, to the north and down dip. See Figure 3 for an illustration of drill section 1450N; additional drill sections are available on INV Metals’ website.
Table 2: Okohongo Drill Results, intersections >0.4% copper
|Hole No.||From (m)||To (m)||Interval (m)||Copper %||Silver g/t||Section|
The thickness of the mineralized zone varies, however, sections of the copper zone reach thicknesses of 20-30 m, and locally up to 45 m, more than double that of most stratiform copper deposits in the Central African Copperbelt of Zambia and the Democratic Republic of the Congo and the Kalahari Copperbelt of Botswana and central Namibia. Reported intersection lengths are interpreted to be approximately true widths. The gentle dip is in strong contrast to much of the steeply dipping copper mineralization in the established African Copperbelts and is optimal for open pit mining.
The variability in grade and thickness of the mineralized intervals may be attributed to the effects of folding and the original permeability of the host rocks. More permeable parts of the interbedded phyllite and dolomite package were subjected to greater fluid movement and have greater amounts of introduced copper, therefore, intersections with a thin and/or low-grade copper intercept do not imply that the limit of the system has been attained.
Copper mineralization at Okohongo and elsewhere on the Kaoko property is similar in age, host lithologies and tectonic setting to the sediment-hosted, stratiform mineralization of the Central African Copperbelt, the premier sediment-hosted copper district. At Okohongo, mapping indicates that the fundamental structural control may be that of favourable host sediments in fault contact with basement uplifts typical of the Central African Copperbelt.
Most copper mineralization on the Kaoko property is confined to specific stratigraphic horizons, either shale and siltstone or sandstone units. The mineralization at Okohongo is variably oxidized to a depth of at least 200 metres. Chrysocolla and malachite are the principal oxide copper minerals, along with minor amounts of azurite, shattuckite and cuprite. Minor, variable amounts of remanent chalcocite and bornite occur as unoxidized kernels within dominantly oxidized mineralization. Several holes were analyzed for acid soluble (oxide) copper to determine the percentage of total copper mineralization which would be amenable to potential recovery by an acid leach extraction process. Table 3 below reports the results of the analyses on hole INVR-001 which management believes demonstrates that the mineralization appears to be amenable to acid extraction.
Table 3: Total Copper vs. Soluble Copper
|Hole No.||From (m)||To (m)||Interval (m)||Total||Soluble||% of Total Copper||Copper %||Copper %||that is Soluble|
Copper mineralization at Okohongo is concentrated in a dark-grey to grey-green phyllitic siltstone interbedded with dolomite of the Lower Omao Formation that overlies Nosib Group red-beds and underlies massive Upper Omao Formation dolomite. These shallowly east-dipping strata form the western limb of a doubly plunging synclinal fold. There is potential for mineralization to occur where the favourable stratigraphy occurs within the syncline, which provides an immediate total target strike length of seven kilometres (see Figures 1 and 4; the target host rocks are enclosed by the dotted lines on each image). Based on the drilling results to-date and interpretation, it appears that the Okohongo system remains open to the south. Northwards, there is a sizeable untested area that could also prove to be underlain by mineralization. To the west, the mineralized horizon appears to daylight at surface.
In addition to the immediate seven kilometres of exploration potential at Okohongo, another 40 kilometres of strike potential for Okohongo-style mineralization is located along the margin of the previously mentioned domal structure. At least two nearby areas within this prospective zone have the potential for significant additional mineralization (see Figure 4). Teck drilled seven diamond drill holes and three percussion holes at the Epunguwe target, five kilometres north-northwest of Okohongo. Results range from insignificant copper and silver values to 21 m of 1.7% copper and 14.1 g/t silver (in a percussion hole from the surface) and 7 m of 2.2% copper and 177.7 g/t silver (in core). Twelve kilometres northwest of Okohongo, the Otjohorowara target area displays essentially identical pinch-out geometry of the favourable host rocks to that seen at Okohongo. INV Metals is currently carrying out detailed mapping in the Otjohorowara area.
Potential quantity and grade of mineralization is conceptual in nature. There has been insufficient exploration to define a mineral resource on the Kaoko property, and it is uncertain if further exploration will result in such property being delineated as a mineral resource.
At the Sesfontein target area INV Metals drilled four reverse circulation holes totalling 582 m to test the Red Valley and Black Ridge showings, two of the 55 copper prospects exposed along the 26 kilometre long Sesfontein target area (see Figure 5). Drill conditions were not ideal, with one hole being abandoned in difficult overburden and as a result, further drilling was deferred until a diamond drill rig is secured. INVR-028 intersected 3 m of 0.2% copper and 2.3 g/t silver from a downhole depth of 107 metres. INVR-029 intersected 1 m of trace copper and 1.9 g/t silver at 95 metres. The Sesfontein area is extensive and remains relatively unexplored.
The Horseshoe target is located in the eastern region of the central claims (see Figure 5). INV Metals completed a six-hole reverse circulation drill program totalling 847 metres. INVR-021 intercepted 2 m of 0.3% copper and 5.0 g/t silver from a downhole depth of 59 metres. INVR-022 intercepted 4 m of 0.9% copper and 22.2 g/t silver from 128 metres. Eight metres of trace copper-silver mineralization was intercepted in INVR-026 at a downhole depth of 158 metres. No further follow-up drilling is planned at the Horseshoe target at the present time.
A second phase drill program is targeted at the Okohongo zone later this year following the completion of further detailed mapping and geochemical surveys which are ongoing at the Okohongo and Otjohorowara areas. A 1,200 m drill program is scheduled to commence in late October at the Manuela target (see Figure 5), where grab samples collected by INV Metals ranged from 0.8% copper and 4.9 g/t silver up to 8% copper and 18 g/t silver. Prioritization and development of the remaining 16 identified target areas is also ongoing due to the prospective nature of the property. INV Metals plans to perform initial exploration work at the Oruwanye target, where Teck outcrop composite grab samples ranged from 0.54% copper and 5.5 g/t silver to 13% copper and 323 g/t silver, in a sample collected over a 50 m by 5 m area.
Quality Assurance — Quality Control Procedures
During reverse circulation drilling each meter was sampled and split by means of a cone splitter mounted below the cyclone into two representative samples, one weighing approximately 30 kilograms and a smaller sample weighing approximately 5 kilograms. Both samples were collected directly from the splitter. The large sample was collected in a clean, unused plastic polyweave bag. The small sample was collected in a clean, unused transparent plastic bag. The downhole depth of the sample was pre-written on each bag. Samples to be analyzed were identified during the logging process. Once a sample was chosen for analysis it was assigned a unique sample number. A pre-printed paper sample ticket was placed in the smaller 5 kilogram sample bag and the sample number was written on the outside of the bag. Provision was made for later insertion of duplicates, blanks and certified standards by the preparation laboratory.
Samples to be analyzed were transported by INV employees to Analytical Laboratory Services located in Windhoek, Namibia, at 71 Newcastle Street, Northern Industrial Area, for sample preparation. The samples were fine enough to not require crushing. A 200 gram split of the sample was produced with a riffle splitter and pulverized using a Siebtechnik (Germany) pulverizer (250cc bowl, hardened carbon steel rings) until 85% of the sample passed 75 microns. A quartz blank was passed through the pulverizer between every sample. The pulverized sample was then split in a riffle splitter to 50 grams. Using predetermined sample numbers employees of Analytical Laboratory Services inserted duplicates, certified standards and blanks every 20 samples in order to monitor contamination and accuracy of the analyses. Each 100-sample sequence contains 85 routine samples, five duplicates, five certified standards and five blanks. The 50 gram pulverized samples were packaged in labelled zip-lock plastic bags. A pre-printed paper sample ticket showing the unique sample number was placed inside each bag.
Activation Laboratories personnel picked up the samples at the Analytical Laboratory Services office in Windhoek and transported the samples to their Windhoek office, located at 267 Cobalt Street, Prosperita. Samples were shipped via SDV Logistics by Activation Laboratories personnel to Activation Laboratories Ltd. located at 1336 Sandhill Drive, Ancaster, Ontario for analysis. After a four acid “near total” digestion, samples were analyzed for 35 elements using a Varian Vista ICP. Samples containing >100 g/t silver were re-analysed using a 30 gram sample subjected to fire assay with a gravimetric finish. Over limit samples containing >10,000 ppm copper or >5,000 ppm lead were subjected to sodium peroxide fusion and acid dissolution followed by ICP/OES analysis. Samples from several holes were also analyzed for acid soluble copper. The soluble copper values were determined by leaching a 0.5 gram sample with 50 ml of 5% sulphuric acid for 60 minutes using an orbital shaker. The leached samples were then diluted to 100 ml volumetrically with purified water, filtered, then analyzed by ICP-OES. To verify the acidity of the leach solutions, the pH was measured on selected samples with varying copper and calcium contents.
Based on INV Metals’ rigorous quality assurance and quality control procedures, 281 samples were re-analyzed by Activation Laboratories. Samples were selected for re-analysis based on their proximity to a certified reference standard that returned a copper or silver value greater than three standard deviations higher or lower than the mean value for that standard. In addition, any two consecutive reference standards falling outside the two standard deviation threshold were considered to have failed. Since every twentieth sample was a reference standard, ten samples above and below a failed standard were re-analyzed. The same protocol was applied to duplicate samples considered to have unacceptably divergent copper or silver values. In addition, 54 random samples were submitted to ALS Chemex Laboratory in Johannesburg as an external check on the results provided by the primary lab. Each of the four reference standards used in the program was represented by two samples for a total of 62 samples submitted.
Comparison of results from the original Activation Laboratory analyses, the Activation Laboratory re-analysis and the ALS Chemex results has identified the possibility of variability in some silver analyses from hole INVR-001. INV believes, but has not verified, that this variability may be a function of the silver mineralogy of those samples. For those specific samples INV has chosen to use the lowest available silver value when reporting mineralized drill hole intersections.
Consulting firm Scott Wilson Roscoe Postle Associates Inc. of Toronto was contracted to carry out a review of INV Metals’ quality assurance — quality control program and procedures, and has advised that the procedures in place meet or exceed industry standards.
The technical and scientific data contained in this press release has been reviewed by, and the press release has been prepared under the supervision of, INV Metals’ Qualified Person, Mr. Scott Jennings, a consultant to the Company.
About INVTM Metals
INVTM Metals is an international mineral resource company focused on the acquisition, exploration and development of base and precious metal projects in Brazil, Namibia and Canada. Currently, INVTM Metals’ primary assets are: (1) its option to acquire 50% of the Rio Novo property, located in Brazil, (2) its option to acquire 50% of the Kaoko property, located in Namibia, (3) its 100% owned Itaporã gold properties, located in Brazil and (4) its option to acquire 50% of the Thorne Lake gold property, located in northwestern Ontario. Please also refer to INVTM Metals’ Management’s Discussion and Analysis dated August 4, 2010, available on SEDAR at www.sedar.com and the corporate presentation on INVTM Metals’ website at www.invmetals.com to view additional details relating to the properties.
This press release contains certain forward-looking statements. These forward-looking statements are subject to a variety of risks and uncertainties beyond INV Metals’ ability to control or predict which could cause actual events or results to differ materially from those anticipated in such forward-looking statements. There is no guarantee that any drill targets or economic mineral deposits will be found on INV Metals’ properties. Forward looking statements involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievement of INV Metals to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Such factors include, among others, risks related to the actual results of current exploration activities, conclusions of economic evaluations, risks associated with mining and mineral exploration activities, uncertainty in the estimation of mineral resources, changes in project parameters as plans continue to be refined, future prices of metals, economic and political stability in Canada, Namibia and Brazil, environmental risks and hazards, increased infrastructure and/or operating costs, availability of future financing, labour and employment matters, and government regulation. For a more detailed discussion of such risks and other factors, refer to INV Metals’ annual information form with Canadian securities regulators available on www.sedar.com or INV Metals’ website at www.invmetals.com.
FIGURE 3: DRILL SECTION 1450N