A Globally Significant Silver-Gold Polymetallic Discovery
The Carangas Project is located about 190 km southwest of Oruro, Bolivia, within the South American Epithermal Belt, which hosts large precious metal deposits and operations in neighbouring countries but remains under-explored in Bolivia. The property comprises three Exploration Licenses (Granville I, Granville II and Colapso) spanning a total area of 40.75 square kilometers, and is road accessible.
In April 2021, the Company announced that it had entered into a Mining Associate Contract with a private Bolivian corporation. Under the Contract, the Company will cover 100% of future expenditures for exploration, mining, development, and production activities and will receive 98% of operational profits once Carangas moves to the mining production stage. The agreement has a term of 30 years and is renewable for another 15 years.
The Carangas Project is hosted within a volcanic caldera system. This system is centered around a Tertiary-aged diatreme. The mineralization process was influenced by the heat gradient from rhyolitic intrusions within the diatreme. This process resulted in the formation of three distinct zones: an upper zone rich in silver, a middle zone dominated by zinc and lead, and a lower zone with a higher concentration of gold. Exploration commenced mid-2021, and over 81,000 m of drilling in 189 drill holes have been completed.
Historical Exploration and Mining
Mining in the district is thought to have commenced in the sixteenth century and continued intermittently until the early twentieth century. The Project, particularly West Dome, contains extensive surface workings, underground mine adits, shafts and associated processing and smelting infrastructure. There is no active mining at present.
Modern mineral exploration, led by local mining interests, began in the early 1980s. The first drill program, comprising nine reverse circulation holes for a total of 1,000 m, was carried out in 1995. Written records for the program report a drill intercept of 116 m at an average grade of 95 g/t silver (from 18 m to 134 m downhole), including 16 m at 325 g/t silver (from 66 m to 82 m downhole), including a 4-m mined-out interval in hole RC-05.
A second drill program was conducted in 2000, also led by a local Bolivian group, with six diamond drill holes for a total of 914 m completed. The results are in line with prior exploration and include a drill intercept of 76 m at an average grade of 90 g/t silver, 0.96% lead, and 0.12% zinc (from 0 m to 76 m downhole), including 8 m at 266 g/t silver, 1.02% lead, and 0.06% zinc (from 26m to 34 m downhole) in hole DDH-01. No recorded exploration activities occurred over the next 20 years until the Company’s involvement.
The Carangas Project is hosted within a volcanic caldera system. This system is centered around a Tertiary-aged diatreme. The mineralization process was influenced by the heat gradient from rhyolitic intrusions within the diatreme. This process resulted in the formation of three distinct zones: an upper zone rich in silver, a middle zone dominated by zinc and lead, and a lower zone with a higher concentration of gold.
Below the 2023 Mineral Resource Estimate conceptual pit constraint exists gold-dominated mineralized material of similar size and grade to the reported mineral resources of the Lower Gold Zone. This mineralized material has the potential to be converted to mineral resources amendable to underground mining pending further evaluation for reasonable prospects of eventual economic extraction. Gold mineralization remains open to the north and northeast at depth.
Regional Exploration Potential
The Company also completed a 3D Bipole-Dipole IP-MT survey in an area of approximately 29 square kilometers over the entire Carangas caldera basin in early 2023. This survey demonstrated that the known gold mineralization system overlays a strong chargeability anomaly in the Central Valley area. In addition, multiple strong IP chargeability anomalies were identified beyond the drilled areas. The Company believes that these anomalies may host mineralization similar to what has been drilled thus far, underscoring the potential for mineral resource growth through additional drilling campaigns.
Preliminary metallurgical testwork consists of scoping-level cyanide leach and flotation testing and is carried out by Bureau Veritas’s Metallurgical Division in Richmond, British Columbia, Canada. Mineralized materials sampled from rejects of selected Carangas drill cores with assays were composited to five samples based on the type of mineralization and degree of oxidization. Host rock sample is altered volcanoclastic rocks of dacitic-rhyolitic composition.
These preliminary test results clearly demonstrate that high recovery rates can be expected for gold using cyanide leaching and for silver, lead, and zinc through conventional cyanide leaching and flotation for silver-lead-zinc mineralized materials. Based on the preliminary metallurgical test results, the following recommendations can be made with respect to the selection of flowsheet for the future process plan:
For gold, cyanide leach and carbon-in-pulp (CIP) may potentially achieve an average of 98.6% gold recovery. Gold doré will be the final product.
For silver-lead-zinc, silver/lead concentrate and zinc concentrate may be produced by sequential selective flotation or gravity concentration. The resultant silver/lead concentrate may be treated by cyanide leach to enable silver doré production.
Inaugural Mineral Resource Estimate
On September 5, 2023, the Company report the inaugural independent National Instrument 43‐101 – Standards of Disclosure for Mineral Projects (NI 43-101) mineral resource estimate (MRE) for its 98%-controlled Carangas silver-gold polymetallic deposit in Bolivia (effective August 25, 2023).
- CIM Definition Standards (2014) were used for reporting the mineral
- The qualified person (as defined in NI 43-101) for the purposes of the MRE is Anderson Candido, FAusIMM, Principal Geologist with RPM (the “QP”).
- Mineral resources are constrained by an optimized pit shell at a metal price of US$23.00/ounce (“oz”) Ag, US$1,900/oz Au, US$0.95/pound (“lb”) Pb, US$1.25/lb Zn, US$4.00/lb Cu, recovery of 90% Ag, 98% Au, 83% Pb, 58% Zn and Cut-off grade of 40 g/t
- Mineral resources are reported inside the property
- Average stripping ratio for the conceptual pit is ~1.8:1. The conceptual pit has a dimeter of approximately 1.4 kilometers and extends to a maximum depth of approximately 600 meters from the Central Valley.
- Drilling results up to June 1,
- The numbers may not compute exactly due to
- Mineral resources are reported on a dry in-situ basis.
- Mineral resources are not Mineral Reserves and do not have demonstrated economic viability.
- Total indicated mineral resources of 214.9 million tonnes (“Mt”) containing 205.3 million ounces (“Mozs”) of silver (“Ag”), 1,588.2 thousand ounces (“Kozs”) of gold (“Au”), 1,444.9 million pounds (“Mlbs”) of lead (“Pb”), 2,653.7 Mlbs of zinc (“Zn”), and 112.6 Mlbs of copper (“Cu”); or collectively 559.8 Mozs silver equivalent (“AgEq”).
- Total inferred mineral resources of 45.0 Mt containing 47.7 Mozs of silver, 217.7 Kozs of gold, 297.9 Mlbs of lead, 533.7 Mlbs of zinc, and 16.8 Mlbs of copper; or collectively 109.8 Mozs AgEq.
- Carangas is a globally significant Ag-Au polymetallic discovery.
- Mineralization starts at or near surface, potentially allowing for open-pit mining with an average stripping ratio for the conceptual pit of approximately 1.8:1 (tonnes of waste : tonnes of mineral resource).
- Below the pit constraint, substantial gold-dominant mineralization, similar in size and grade to the reported gold domain, has the potential for conversion to underground mineable resources pending further evaluation for reasonable prospects of eventual economic extraction.
- Favorable initial metallurgical test work indicates laboratory‐based recoveries of up to 90% for silver and 98% for gold based on a combination of flotation and cyanide leaching.
Cautionary Note: Estimations of mineral resources are inherently forward-looking. Risks relating to legal, political, environmental, or other factors that could materially affect the potential development of the mineral resources or mineral reserves include political and economic risks in Bolivia, the regulatory environment in Bolivia, community relations and social licence to operate, acquisition and maintenance of permits and Government approvals, operations and explorations subject to Governmental regulations, impact of environmental laws and regulations, environmental protection, title to mineral properties, outcome of future litgation or regulatory actions, and other factors described under the heading “Risk Factors” in the Company’s annual information form for the year ended June 30, 2022 (“AIF”), its management discussion and analysis for the year ended June 30, 2023 (“MD&A”) and its other public filings which are incorporated by reference hereto. This list is not exhaustive of the factors that may affect the mineral resources or mineral reserves.
Resource Estimation Details:
The MRE is based on a geological model that incorporated assay results received by New Pacific for the Carangas Project up to June 1, 2023. This included assay results from all 189 drill holes completed from June 2021 to April 2023. The MRE is reported inside the Carangas Project’s property boundary and constrained by potential open pit mining scenarios and uses a cut-off grade of 40 grams per tonne of AgEq. A mineralization wireframe was constructed by New Pacific and validated by RPM as a reproducibility/materiality protocol. The domain was reviewed by the QP and no major biases were identified in the model. The model was used for sample constraint and block model construction.
RPM completed an Inverse Distance Squared (ID2) estimate on these domains. Prior to estimation, drill hole data were submitted into exploratory data analysis to domain verification and then composited to 1.5 m long intervals and samples were capped for all variables within each domain where required. Silver values were capped at 7,000 g/t Ag, and gold values were capped at 40 g/t Au. The parent block size was 5m E x 5m N x 5m RL with no sub‐blocking employed. A total of 14,953,680 blocks were generated to cover the entire mineralized area. The model origin is 538.490 E, 7.904.850 N, 4.100 RL, and there is no rotation in the model. As mineralization is hosted in various types of volcanic rocks, the densities of mineralized materials are estimated using the ID2 method. The number of samples used to estimate density varies from 1 to 4 samples. Density values vary between 1.2 to 3.48 in the block model. Mineral resources grade was completed using the ID2 method for each variable in each domain. No records of historical mining are available. Compared to the size of the mineralization system, the estimated mined tonnage is minimal; hence no depletion has been applied in the MRE. Mineral resource classification was completed using an assessment of geological and mineralization continuity, data quality and data density. Average distance of samples was used to classify the block with an average distance of 70m used as threshold for indicated / inferred definition. The block model was assigned as indicated and inferred mineral resource categories.
Quality Assurance, Quality Control & Data Verification
The QP determined sample preparation, analytical, and security protocols employed by New Pacific to be acceptable. The QP reviewed the quality assurance and quality control (“QA/QC”) procedures used by New Pacific including certified reference materials, blank, duplicate, and umpire data, and identified no major bias. The QP determined that the assay database was adequate for mineral resource estimation. The QP determined that the use of a reasonable number of different control samples is robust and returns a good variety of verification throughout the whole process, and the umpire lab check analysis gives a good level of reproducibility of the database. The QP found that the insertion ratio of control samples is 24%, which is higher than the industry benchmark (15-20%). The QP is of the opinion that the results are acceptable and accomplished within industry standards and recommended that New Pacific maintain a continuous QA/QC program for new exploration drill campaign to maintain the database quality.
The MRE and data verification was completed by RPM. Anderson Candido, FAusIMM., Principal Geologist with RPM, is the QP for the purposes of the MRE. The scientific and technical information contained herein has been reviewed and approved by the QP. The QP has verified the information disclosed herein using standard verification processes, including the sampling, preparation, security and analytical procedures underlying such information, and is not aware of any significant risks and uncertainties or any limitations on the verification process that could be expected to affect the reliability or confidence in the information discussed herein.
Further details supporting the geological model, estimation procedure and metallurgical testwork will be available in a NI 43‐101 technical report in respect of the Carangas Project (the “Technical Report”). The Technical Report will be posted under the Company’s SEDAR+ profile at www.sedarplus.ca within 45 days from the September 5, 2023 news release.