News
New Oroperu pegs Tres Cruces at 2.47M oz Au indicated
2021-02-01 08:05 ET - News Release
Mr. K. Wayne Livingstone reports
NEW OROPERU ANNOUNCES NEW RESOURCE ESTIMATES OF LEACHBLE GOLD AT TRES CRUCES: 425,000 OUNCES OF OXIDE RESOURCE AND 205,000 OUNCES OF LEACHALBLE SULFIDE
New Oroperu Resources Inc. has received a gold resource estimate for its Tres Cruces project in north-central Peru. The estimate includes 425,000 ounces of oxide Au mineralization (leachable) and 205,000 ounces of leachable sulfide Au mineralization within a pit-constrained total Indicated Resource of 2.47 M. oz Au, which includes all Au-bearing oxide and sulfide mineralization. The resource estimate has been determined by James N. Gray, P.Geo. of Advantage Geoservices Limited. Tres Cruces is 100% owned by New Oroperu, subject to a 1.5% Net Smelter Return. (See also Note 1 at the end of this news release).
Tres Cruces Highlights:Leachable Resources:425,000 ounces of gold in oxide material at 1.37 g/t in the Indicated category, contained in 9,636,000 tonnes, using a 0.3 g/t Au cut-off (Table 1).205,000 ounces of gold in leachable sulfide material at 1.12 g/t, in the Indicated category, contained in 5,707,000 tonnes, using a 0.3 g/t Au cut-off (Table 1). Total Mineral Resource:2.474 million ounces of gold at 1.66 g/t in the Indicated category, contained in 46,475,000 tonnes of oxide and sulfide material. Non-leachable sulfide resources are estimated using 0.9 g/t Au cut-off.104,000 ounces of gold at 1.26 g/t in the Inferred category, contained in 2,561,000 tonnes.Currently defined oxide mineralization demonstrates the potential for an economic standalone heap leach operation, with depth expansion allowing extraction of leachable sulfides.Potential for additional Resources provided from recoverable silver.Company is exploring economic options to treat sulfide mineralization by alternative processing.
Wayne Livingstone, President, commented, "This break-out of leachable resources suggests that a stand-alone development may be viable on Tres Cruces. We are excited to be taking control of the project and further advancing it through a production scenario."
"We believe that the estimated leachable gold resources would have a meaningful role in any strategic advancement of the project by the Company. There are also opportunities for us to identify more leachable (oxide and sulphide) gold resources on Tres Cruces, and nearby, which would enhance project economics. In a potential production scenario, the oxide mineralization would be processed first, followed by the leachable sulphides and thereafter the remaining sulphide material would be processed through a plant facility, to be developed at that time. We view this leachable mineralization as a potential near term cash flow engine that could significantly offset the initial capital costs of any larger operation."
"The proximity of Tres Cruces with Barrick's nearby Lagunas Norte mine offers the possibility of operational synergies and this will be a factor for our consideration as we advance Tres Cruces," continued Mr. Livingstone.
CATEGORIES OF ESTIMATED RESOURCES AND CUT-OFF GRADES Oxide Leachable sulphide Sulphide (0.3 g/t Au cut-off) (0.3 g/t Au cut-off) (0.9 g/t Au Cut-off) Total Resource classif- Tonnes Au Au oz Tonnes Au Au oz Tonnes Au Au oz Tonnes Au Au oz ication (000s) (g/t) (000s) (000s) (g/t) (000s) (000s) (g/t) (000s) (000s) (g/t) (000s) Indicated 9,636 1.37 425 5,707 1.12 205 31,132 1.84 1,844 46,475 1.66 2,474 Inferred 487 0.75 12 361 0.60 7 1,713 1.55 85 2,561 1.26 104
Note: CIM definitions were followed for Mineral Resources. Totals may not agree due to rounding.
Sensitivity Table of Estimated Resources and Cut-off GradesOxide & Leachable Sulfide Resources Sulfide Resources Cut-off (g/t Au )Resource Classification Tonnes (1,000s) Au (g/t) oz Au (1,000s) 0.2 Indicated 15738 1.25 .64 633 19 Inferred 939 0.3 Indicated 15343 1.28 .69 630 19 Inferred 84 0.4 Indicated 14729 1.31 .78 622 17 Inferred 659 0.5 Indicated 13562 1.39 .89 605 14 Inferred 502 Cut-off (g/t Au) ResourceClassification Tonnes (1,000s) Au (g/t) oz Au (1,000s) 0.7 Indicated 43692 1.56 1.38 2,139 97 Inferred 2185 0.8 Indicated 36292 1.70 1.46 1,985 92 Inferred 1962 0.9 Indicated 31132 1.84 1.55 1,844 85 Inferred 1713 1.0 Indicated 26844 1.99 1.64 1,714 78 Inferred 1476
Mineralization type was used to subdivide this resource through the generation of two surfaces. The bottom of oxides, as well as the bottom of a zone of leachable sulfide material, were determined from drill information, based on a mix of analytical (sulfide sulfur values) and logged redox observations. In general, S2- values <0.4% denoted oxide, and values between 0.4 and 3.4% S2- indicated a zone of leachable sulfide mineralization immediately below the upper oxide zone.
Methodology for the Resource Estimate
The depth of oxide was modelled based on 286 drill holes. Interpolated and actual points were then used to create the lower oxide bounding surface. The same process used 139 holes to generate the bottom of leachable sulfide surface.
A mineralized domain, at a threshold value of 0.2 g/t Au, was generated by an indicator estimation method. This separation of mineralized from background-grade material was used as control in grade estimation.
Assays from 327 holes were composited to a length of 3m for use in grade estimation. Gold grades were estimated inside and outside the mineralized shells by ordinary kriging. Resource blocks have dimensions of 10 x 10 x 5m.
Block densities were assigned by lithology based on 2,713 density measurements made on drill core. The average density in the oxide material is 2.24 t/m3 and the average density for the sulfide material is 2.38 t/m3.
Measures were taken to ensure that the resource meets the condition of "reasonable prospects of eventual economic extraction". An optimised resource pit shell was generated, based on the Indicated plus Inferred Mineral Resource. Pit optimization parameters are listed in Table 3.
Blocks inside the optimized pit shell were classified as Indicated, where the average distance to the closest three holes is within 50 m, and as Inferred where the average distance to the closest three holes is within 80 m. Ninety-nine percent of oxide resource blocks, and virtually all total resource blocks, were estimated by three or more holes.
Table 3: Pit Optimization ParametersParameter Value Au Price $1,500 Royalty 0.015 Mining Cost US$1.90/t mined G&A $2.00/t Dilution 0% Mining Loss 0% Oxide Heap Leach Cost $2.37/t Oxide Heap Recovery 81.70% Sulfide Leach Cost $3.30/t Sulfide Leach Recovery 65% Sulfide Cost $28.49/t Sulfide Recovery 88%
Silver Mineralization
Silver is not included in the mineral resource estimate, but there are silver assays available from some of the project's drill campaigns and silver is shown to be recovered in metallurgical test work. Available silver assays generally show low correlation with gold values.
To have an impression of a potential contribution by silver, grades were interpolated using a similar technique to that documented for the gold resource. Specifically, a zone of &#8805;0.5 g/t Ag was generated using indicators and Ag grades were interpolated inside and outside that volume.
Indications are that silver grades are generally low and concentrated mainly in the deeper, sulfide portion of the gold deposit. Based on this analysis, overall silver grades would be expected to range between 1.5 and 2.5 g/t potentially adding 2.5 to 3.5 million ounces of silver to the gold resource.
Geology of Tres Cruces
The Tres Cruces deposit is a low to intermediate sulfidation type epithermal system. Gold mineralization is hosted by a bimodal suite of andesitic to rhyolitic flows, domes, breccias, and volcaniclastics. Gold occurs with a fine grained dark arsenical pyrite, generally disseminated in its volcanic host and along structural zones and lithologic contacts. Hydrothermal alteration in the core of the deposits is dominated by illite with subordinate quartz, kaolinite, and smectite. Oxidation of the pyritic mineralization has occurred from a few meters up to 100 meters below surface, developed primarily in rhyolitic host rocks. Underlying sulfide mineralization is primarily hosted by andesitic rocks.
Metallurgy
Metallurgical testing programs have been completed during various exploration stages of the Tres Cruces project since 1998. These test programs included both oxidized mineralization and sulfides. Various metallurgical tests focusing on the oxides, included column leach tests, CIL cyanidation, bottle rolls and individual cyanide quick leach tests. Twenty CIL cyanidation, eight bottle roll and over 200 cyanide quick leach tests were completed on oxide mineralized core from over 40 drill holes.
Column leach tests on six composite samples averaged 81.7% recovery for gold. These tests were terminated in 16 days or less and showed fast recovery with increasing recoveries on termination. Bottle roll tests completed on these samples as well, averaged 83.0% gold recovery. One batch of CIL cyanidation tests containing low sulfur, which was deemed as oxidized mineralization, had an average recovery of 90.8% based on 10 composites in 6 drill holes.
The low sulfide and oxidized mineralization is responsive to CIL cyanidation. The column leach testing which averaged 81.7% recovery for gold was selected to reasonably represent recovery for purposes of pit optimization and determination of the oxide resource estimates.
Sulfides have shown a wide variation in gold extraction with cyanidation testing. Direct cyanide leach and CIL tests indicate low sulphur bearing sulfides are amenable to heap leaching. In this resource estimate, the balance of the higher sulfide mineralization is considered to be treated by flotation-pressure oxidation-CIL, in which test work has indicated gold recoveries of 90% and higher. Some test work in this sulfide category has recoveries amenable to other processing methods but additional analysis and test work would be required to quantify those results.
Qualified Persons and Technical Information
The updated mineral resource estimate was prepared by James N. Gray, P.Geo., an Independent Qualified Person as defined by National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101) in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Standards on Mineral Resources and Mineral Reserves, adopted by CIM Council, as amended.
The full technical report, which is being prepared in accordance with National Instrument 43-101 Standards of Disclosure for Mineral Projects ("NI 43-101") will be available on SEDAR (www.sedar.com) under the Company's issuer profile within 45 days from this news release.
About New Oroperu Resources
New Oroperu is a junior exploration company based in Vancouver, B.C., which owns the Tres Cruces gold project in Peru. The Tres Cruces gold project currently hosts a mineral resource estimate of 2.474 million ounces of gold at 1.66 g/t in the Indicated category, which includes 630,000 ounces of leachable gold resources.
Jeffrey D. Rowe, P.Geo. and James N. Gray, P.Geo., Qualified Persons as defined by NI 43-101, have reviewed and approved the technical content used in this News Release.
Note 1:
Reference is made to the January 5, 2021 News Release of the Company wherein it announced that the option previously held by Minera Barrick Misquichilca S. A. ("MBM") to acquire an interest in the shares of the company's subsidiary, Aurifera Tres Cruces S. A., ("ATC"), holder of the Tres Cruces property, expired unexercised on December 31, 2020, (the last day for exercise expressly set out in the option as a condition of exercise) and accordingly, MBM and its affiliates, including Barrick Gold Corporation, ("Barrick"), had no further interest in the ATC shares or the Tres Cruces property. The Company requested certain assurances from Barrick and MBM in connection with the expiration of the option. In response, Barrick stated it believed the Company misstated MBM's rights going forward. The Company has carefully considered its position and stands by its conclusion that any right MBM previously held has expired.
We seek Safe Harbor.