Cordoba Minerals Reports High-Grade Mineral Resources for the Alacran Copper and Gold Deposit
TORONTO, ONTARIO--(Marketwired - Jan. 5, 2017) - Cordoba Minerals Corp. (TSX VENTURE:CDB)(OTCQX:CDBMF) ("Cordoba" or the "Company") and its joint-venture partner, High Power Exploration Inc. ("HPX"), a private mineral exploration company indirectly controlled by mining entrepreneur Robert Friedland's Ivanhoe Industries, LLC, are pleased to announce an initial Mineral Resource estimate for the Alacran Copper-Gold Deposit in Colombia.
Highlights (the figures referenced are at end of news release)
- The initial, pit-constrained, Inferred Mineral Resource for the Alacran Deposit is 53.52 million tonnes at 0.70% copper and 0.37 g/t gold, or 0.95% copper equivalent (CuEq), including 7.37 million tonnes at 2.14% copper and 0.41 g/t gold above 1% copper (Cu) cut off.
- The Inferred Mineral Resource is contained within a shallow, north-south trending mineralized corridor that is approximately 1.3 kilometres long and up to 355 metres wide.
- Mineral resources are reported within a conceptual open-pit shell which extends for the full length of the 1.3 kilometre corridor and to a depth of 220 metres below surface (see figure 2 and 4). The broad horizontal widths of mineral resource zones from surface are considered favorable for potential open-pit development at relatively low potential strip ratios, subject to the demonstration of economic viability (see figures 2, 4, 5 & 6).
- Copper-gold mineralization has been intercepted in drill holes below the conceptual pit shell and also at depths greater than 220 metres below surface; however, this mineralization was not included in the initial Inferred Mineral Resource due to insufficient drilling at the Mineral Resource cut-off date (see figures 4, 5 & 6). This mineralization provides the joint venture with immediate drilling targets which could materially expand the Inferred Mineral Resource.
- The Alacran mineralized system remains open to depth. Surface copper-gold geochemical anomalies also indicate significant potential for additional mineralized zones to the east and west of the Mineral Resource.
- The potential for the discovery of the mineralizing source for the high-grade copper and gold at Alacran is considered strong. Drill targets have been identified and will be aggressively tested by the joint venture this year.
Table 1: El Alacran Mineral Resource as at October 27, 2016
|(Mt)||Copper (%)||Gold (g/t)||Copper (Mlb)||Gold (Koz)||CuEq (%)||CuEq (Mlb)|
* Pit constrained mineral resources are reported in relation to a conceptual Whittle pit shell. Mineral resources are not mineral reserves and do not have demonstrated economic viability. All figures are rounded to reflect the relative accuracy of the estimate. Mt: millions of tonnes; Mlb: millions of pounds; Koz: thousands of ounces.
**Copper equivalent grades are based on estimated copper and gold values, metal prices $2.50/lb Cu and $1300/oz gold (Au). Metal prices are not constant and are subject to change.
*** Pit constrained mineral resources are reported at a copper equivalent cut-off of 0.3% and applying assumed metal recoveries of 90% for Cu and 80% for Au. Note no metallurgical test work has been undertaken by Cordoba and the recoveries are estimates only.
**** Capped copper and gold assay composites were interpolated by ordinary kriging constrained within geologically constrained copper-gold grade shell boundaries (Figure 3).
The Mineral Resource estimate was independently prepared by Mining Associates Limited ("MA"), a leading global geological, resource and mining consultancy, and is reported in accordance with National Instrument 43-101 ("NI 43-101") and the 2014 CIM Definition Standards. The Inferred Mineral Resource estimate is based on 20,200 metres of diamond drilling completed as at October 27, 2016.
Mario Stifano, President and CEO of Cordoba, commented, "We are pleased with the initial mineral resource which demonstrates the potential for the Alacran Project to host a significant tonnage of high-grade, potentially open-pittable copper-gold mineralization. This is just the beginning as our ongoing, aggressive drilling program is aimed at growing the mineral resources in size and confidence levels, extending high-grade copper- and gold-rich mineralized zones and drilling additional exploration targets with potential to add a new and significant exploration front to Alacran."
Composite lengths and high-grade cuts based on spatial distribution and probability plots were applied as follows:
- Copper and gold assay data was composited to two metres down hole within geological domains; a copper grade cap was applied at the 97.5th percentile in high-copper domains and 98th percentile in the lower grade domains.
- Gold assays were composited to two metres down hole within copper domains and were capped near the 98th percentile.
The geological resource is constrained by sub-block within seven wireframes ("grade shells") in domains based on lithology, structure and a minimum sample grade of 0.3% CuEq and may include minor internal dilution (e.g. Figures 3, 4, 5 & 6). Gold, iron and sulfur are constrained by the low-grade CuEq shells, iron and sulfur are also estimated unconstrained to inform the waste blocks. Separate grade-shells were created for high-grade copper and gold based on grade >1% Cu and > 1g/t Au respectively.
The constraining grade shells are modelled within a corridor, elongate approximately 1.3 kilometres north-south, of up to 355 metres horizontal width and interpolated/extrapolated to depths locally reaching 300 metres from surface (Figures 2 and 3).
Copper and gold grades were interpolated into the constrained block model by domain using ordinary krige techniques. Kriging parameters are derived from a study of variography by domain. The block model was validated by statistical and visual comparison of data and estimated grades and by alternate estimation methods.
Routine bulk density measurements (747) show some variation with an average bulk density of 3.01 t/m3. Bulk density was calculated based on an iron regression, BD=0.0292 x Fe% + 2.5599, utilising block iron contents estimated as outlined above.
Mineral Resources have been classified as Inferred. Resource classification is based on confidence in grade continuity and geological models of the primary commodities (Cu, Au). The inferred resource lies above -30 mRL and within a conceptual Whittle pit shell (Figures 2, 5, & 6). Drill spacing in Mina Norte approximates a 40 x 40 m grid, drilling at Mina Seca has one to two holes per section.
Mineral Resources are reported at various copper grade ranges, within the 0.3% CuEq shell, clearly identifying the proportion of mineralization below 0.3% copper that is enriched in gold in the resource (Table 2) in both resource domains (Mina Norte & Mina Seca, Figure 3). Tonnages are rounded to the nearest million tonnes, copper grades are rounded to two decimal places and accessory minerals are rounded to one decimal place. Rounding as required by reporting guidelines reflect the accuracy of the estimates and may result in apparent summation differences between tonnes grade and contained metal.
Table 2: Inferred Mineral Resource at El Alacran resource at various Copper Cut-offs (total inferred resource above 0.3% CuEq and within conceptual pit)*
|Deposit||Cut Off||(Mt)||Copper (%)||Gold (g/t)||Copper (Mlb)||Gold (Koz)||CuEq (%)||CuEq (Mlb)|
|Mina Norte||0.0 to 0.3||0.69||0.27||0.31||4||7||0.47||7|
|0.3 to 1.0||28.82||0.52||0.27||328||255||0.70||445|
|Mina Seca||0.0 to 0.3||4.35||0.24||0.65||23||91||0.68||65|
|0.3 to 1.0||12.29||0.46||0.49||125||193||0.79||214|
|Total||> 0.3% CuEq||53.52||0.70||0.37||827||644||0.95||1,122|
*Mineral Resources are not Mineral Reserves do not have demonstrated economic viability. Mineral resources are reported above a conceptual pit shell, and using a copper equivalent cut-off of 0.3% and apply assumed metal recoveries of 90% for Cu and 80% for Au. No metallurgical test work has yet been undertaken by Cordoba.
Outside of the Inferred Mineral Resource, there is unclassified copper-gold mineralization identified in the grade shell models that either lacks confidence in grade and geological continuity (e.g. Mina Este, Figure 4, legend item 4) or is at depth below the -25m RL This mineralization provides immediate drilling targets for potential mineral resource additions.
Further drilling may be expected to increase the confidence levels in, and also potentially add, mineral resources. The Company expects to update the Mineral Resources during the second quarter of 2017 after the expected completion of its current drilling program. The Alacran system remains open to depth along much of its strike length and surface copper-gold geochemical anomalies indicate the potential for largely untested mineralized zones to the east and west of current mineral resources.
The Joint Venture has an option (the "Option") to earn a 100% interest in the Alacran Project by completing the remaining commitments (see Cordoba news release dated October 21, 2015):
- A US$250,000 payment to Sociedad Ordinaria de Minas Omni ("OMNI") on the 24-month anniversary of signing the Letter of Intent ("LOI").
- A US$1,000,000 payment to OMNI on the 24-month anniversary of completion of the Definitive Agreement.
- Cordoba will file with the Colombian government for the relevant approvals to conduct activities of construction and commercial production at Alacran before June 30, 2018.
- A US$14,000,000 payment to OMNI when the environmental license and all other approvals, permits or licenses required to commence the construction and operation of a commercial mine at Alacran have been granted on a final basis by the Colombian government.
Figure 1: Plan view of Alacran geological model showing generally west-dipping lithostratigraphy, with mafic to intermediate volcanics & volcaniclastics in the east and footwall to the main copper-gold mineralised zones hosted mainly by avolcaniclastic -epiclastic sequence that is intruded by intermediate sills and also larger dioritic bodies in the west and north. Mineralization also locally overprints the intrusions
Figure 2: Plan view of copper-gold mineralization "grade" shells, drill-hole traces and conceptual Whittle pit shell
Figure 3: 3D view (towards north-east) of west-dipping "grade" shells under Lidar topography, draped by surface imagery
Figure 4: Copper-gold mineral resources in the Inferred category and unclassified mineralized material in relation to a conceptual Whittle pit shell and drill-hole traces, 3D view towards northeast
Figure 5: Section 855740mN showing drilling results and the broad width of Inferred mineral resource copper grades within a conceptual pit. Copper-gold mineralization may extend to depth below the resource blocks and also below the conceptual pit
Figure 6: Section 855720mN showing drilling results and the broad width of Inferred mineral resource copper grades within a conceptual pit. Copper-gold mineralization may extend to depth below the resource blocks and also below the conceptual pit. Figure 4 & Figure 5 may be compared to give an impression of the north-south continuity of mineralization