Xtierra announces increased resource estimate for Bilbao project
- Indicated resources increase by 169%; Inferred resources increase by 68%
The new resource estimate shows a 169% increase from the
The following table summarises the overall results of the resource estimation completed for the Bilbao Deposit, using a 3% Zn(Eq) cut off (includes sulphide, oxide and mixed ore categories):
Resource Category Tonnage Lead Copper Zinc Silver ----------------- ------- ---- ------ ---- ------ (million tonnes) (%) (%) (%) (gpt) ---------------- ---- ---- ---- ----- Indicated Resources 9.68 2.09 0.21 2.43 59.40 Inferred Resources 4.04 1.55 0.18 1.43 53.64
In the Indicated category, sulphide ore types represent 35%, mixed oxide and sulphide ore types represent 22% and oxide ore types represent 44% of the total Indicated resource. For the purpose of determining resources at various cutoff grades, zinc equivalent values were determined, based on the average LME metal prices during the months of October to
The report was prepared by independent consulting mining geologist, Richard T.G. Parker, C.Eng., a 'qualified person' within the meaning of NI 43-101 - Standards of Disclosure for Mineral Projects of the Canadian Securities Administrators.
The new resource estimate has been calculated at a 3% Zn(Eq) cut off rather than a 6% Zn(Eq) cut off used previously due to the intention to develop the deposit primarily by open pit mining methods. Revised density values were also applied for each of the designated ore-types. Results of subsequent infill drilling have also been included and additional sampling of the existing surface pits and historic underground development, including detailed surveying, has enabled additional resources to be categorized as Indicated.
The block models were filtered by ore type and grade to allow resource estimations according to domain, resource category, ore type and cut-off grade.
The 50 metre drill grid used at Bilbao is considered adequate for geological and grade continuity between intersections in adjacent drill holes to be reasonably assumed within the Core Domain. Blocks interpolated by 40m search ellipsoid within the Core Domain are therefore considered to fulfill the criteria for Indicated Resources.
Most mineral zones outside the Core Domain are defined by single drill intersections allowing geological and grade continuity to be assumed with a lower level of confidence. Blocks interpolated by 50m search ellipsoid both within and outside the Core Domain are therefore considered to fulfill the criteria for Inferred Resources.
Relevant diamond drill data (based on 53 holes totaling 13,650 metres) were reviewed, validated and incorporated into a Datamine database that comprised assays (including ore type), geology, surveys and collars. Composite samples were calculated for 1 metre intervals. Interpolation into 10mx10mx10m Block models was carried out for a Core Domain and for an Outer Domain using search ellipsoids with appropriate ranges and orientations. Grade model plots were combined or overlain with drillhole plots and geological cross sections to enable verification that the block grades in most areas are in close conformity to the geological interpretation and in particular to the extent and orientation of interpreted mineral zones.
The following table outlines the Bilbao resource estimate by ore type and category: ------------------------------------------------------------------------- INDICATED CATEGORY ------------------------------------------------------------------------- Cutoff % % % g/t tonnes tonnes ORE ---------------------------------------------------------------- TYPE ZnEq tonnes Pb Cu Zn Ag Pb Cu ------------------------------------------------------------------------- SULPHIDE 3 3,298,802 2.02 0.21 2.89 61.62 66,488 6,858 ------------------------------------------------------------------------- MIXED 3 2,156,057 1.81 0.16 2.58 59.73 38,982 3,384 ------------------------------------------------------------------------- OXIDE 3 4,229,459 2.28 0.25 1.99 57.51 96,475 10,405 ------------------------------------------------------------------------- TOTAL 3 9,684,317 2.09 0.21 2.43 59.40 201,945 20,647 ------------------------------------------------------------------------- -------------------------- INDICATED CATEGORY -------------------------- tonnes tonnes ORE ------------------- TYPE Zn Ag -------------------------- SULPH- IDE 95,302 203 -------------------------- MIXED 55,656 129 -------------------------- OXIDE 84,038 243 -------------------------- TOTAL 234,996 575 -------------------------- ------------------------------------------------------------------------- INFERRED CATEGORY ------------------------------------------------------------------------- Cutoff % % % g/t tonnes ------------------------------------------------------------------------- ZnEq tonnes Pb Cu Zn Ag Pb ------------------------------------------------------------------------- SULPHIDE 3 820,294 1.29 0.13 1.54 31.06 10,621 ------------------------------------------------------------------------- MIXED 3 1,371,743 1.25 0.15 1.48 61.78 17,180 ------------------------------------------------------------------------- OXIDE 3 1,843,949 1.89 0.20 1.34 57.63 34,893 ------------------------------------------------------------------------- TOTAL 3 4,035,987 1.55 0.17 1.43 53.64 62,694 ------------------------------------------------------------------------- ------------------------------------- INFERRED CATEGORY ------------------------------------- tonnes tonnes tonnes ------------------------------------- Cu Zn Ag ------------------------------------- SULPHIDE 1,092 12,659 25 ------------------------------------- MIXED 2,049 20,333 85 ------------------------------------- OXIDE 3,760 24,660 106 ------------------------------------- TOTAL 6,901 57,652 216 -------------------------------------
The average grade of the indicated resources decreased from 10.1% to 6.7% zinc equivalent (Zn(Eq)) as a result of the lower cut off used. The new Indicated resource contains 84% more zinc, 104% more lead, 95% more copper and 81% more silver than the
Additional Resource Potential -----------------------------
The independent report confirms that potential exists to increase the Bilbao resource, particularly at depth to the south and southwest where drill hole X40, intersected 13.4 metres grading 6.8% lead, 5.1% zinc and 79.5 g/t silver and hole X26 (not included in the resource) intersected high grade silver veins, including 3.0 metres grading 1.3 kilograms per tonne silver. These holes lie on the southern boundary of the drill grid.
The report also indicates further potential to increase the resource may also exist to the northwest where hole X42, collared more than 100 metres outside the drilled grid, intersected 8.75 metres of massive pyrite with only minor base metals from 149.25 metres to 157.00 metres. This hole intersected several low grade base metal zones and a higher grade intersection over 1.0 metre from 181.0 metres to 182.0 metres, assaying 7.32% lead and 170g/t silver (not included within the present resource estimate). The intersections in drill hole X42 occur beneath almost 50m of granite and indicate blind, untested potential in this direction. Step-out drilling in this area has confirmed an extension of thin mineralization at the granitic contact.
Xtierra is planning an additional drilling programme as part of the final phase of the Feasibility Study which will better define the oxide resource in the northern part of the deposit which is currently classified as Inferred with sufficient confidence to elevate it to the Indicated category as well as additional deep holes to the south to ascertain if further sulphide resources persist south of the existing drill grid and also on the eastern side of the deposit.
Commenting on the updated resource estimate, Xtierra's President & CEO, Terence McKillen, stated, "We are very pleased to report the substantial increases in both Indicated and Inferred resource categories at Bilbao and confirmation of the excellent upside for additional resources to be found to the southwest and northwest where step-out drilling is planned."
"The independent report also concludes that the potential to identify additional mineralized bodies within Xtierra's large exploration holdings in the general Bilbao area is excellent."
Feasibility Study -----------------
The new resource estimate is a component part of a two phase Feasibility Study currently being conducted on the Bilbao project. Other component parts include metallurgical testing (including a pilot plant test of the oxide process), environmental and socio-economic studies, hydrological and geotechnical studies, civil engineering and preliminary economic analyses.
Qualified Person ----------------
Information of a scientific or technical nature contained in this release has been prepared by or under the supervision of
Richard T.G. Parker -------------------
Richard T.G. Parker is an independent consulting mining geologist. He received the degree of Bachelor of Science in Geology from the University of Newcastle upon Tyne, England in 1968 and is a Chartered Engineer registered with the Engineering Council (UK), a Professional Member of the Institute of Materials, Minerals and Mining and a Fellow of the Geological Society of
A copy of the Parker report will be filed on SEDAR.
About Xtierra Inc. ------------------
Xtierra Inc. is a
Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or the accuracy of this release.
For further information: visit www.xtierra.ca or contact: Terence McKillen, President & Chief Executive, (416) 362-8243; Tim Gallagher, Director, (416) 925-0090; Alejandro Alanis, Director Finance & Administration (Mexico), +52 (492) 925-0804
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