The information on the Escalones Project contained herein was derived from the NI 43-101 Technical Report entitled “Mineral Resource Estimate for the Escalones Copper Project, Santiago Metropolitan Region, Chile” and dated August 18, 2020, with an effective date of June 30, 2020 and filed on SEDAR. Please refer to this Technical Report for important technical and other disclosures.
The Escalones copper-gold porphyry project lies 35 km east of El Teniente, one of the world’s largest underground copper mines, and within the renowned Chilean porphyry copper belt that runs north-south in the central Andes Mountains. The project has excellent infrastructure, including road access, electricity, access to seaports, and a gas pipeline that crosses the 70 square km property.
The Escalones deposit was discovered in 1996 through greenfield exploration work by Ralph Fitch, former President and CEO of General Minerals Corporation, and Felipe Malbran, the former Vice President of Exploration, South America.
Mineralization & Geology
Escalones has Indicated resources of 185 million tonnes of 0.33% copper (0.37% CuEq) and additional Inferred resources of 254 million tonnes of 0.39% copper (0.43% CuEq), based on nearly 25,000 metres of drill core from 53 holes. Significant molybdenum, gold and silver accompany the copper. The mineralization sits within a four square-kilometer area of hydrothermal alteration comprising quartz-sericite, potassic, and calc-silicate alteration assemblages. Coincident copper, gold and silver geochemical anomalies are associated with replacement-style “skarn” mineralization hosted in calcareous sedimentary rocks that flank central porphyritic intrusive rocks with porphyry-style (fracture-fill and disseminated) mineralization.
Copper mineralization at Escalones occurs primarily as the sulphides chalcopyrite, bornite, and covellite, which are partially to completely replaced within about 300m of the surface with secondary copper oxides, sulphates and carbonates. This replacement has led to higher grades at shallower depths, and, since the mineralization sits within a high-standing ridge, makes it ideal for surface mining.
A NI 43-101 Technical Report prepared by Hard Rock Consulting, LLC titled, “Mineral Resource Estimate for the Escalones Copper Project, Santiago Metropolitan Region, Chile” and dated August 18, 2020, with an effective date of June 30, 2020 (the “Escalones Technical Report”) updated the maiden resource estimate of 2013 (see link at top of page). Approximately two-thirds of the estimated resource occurs in the oxidized enrichment zone above the sulphide mineralization. Assuming this mineralization proves to be favourable to a heap leach scenario, the mining costs could be lowered, which would result in a lower copper-only cutoff.
The recovery of gold and silver would have to be evaluated on a possible on-off leach pad to see if recovery of these metals would be economic through this processing method.
Escalones Resource Estimate (June 30, 2020)
*Copper Equivalent (CuEq) is calculated based on a long-term copper price of US$3.23/lb; gold price of US$1,580/oz; silver price of US$18.63/oz; assumed combined operating ore costs of US$11.50/t (process, general and administrative and mining taxes); refining & smelting costs of $0.25/lb of CuEq; metallurgical recoveries of 75% for copper, 55% for gold and 65% for silver, and a 2% royalty.
Mineral resources that are not mineral reserves do not have demonstrated economic viability. Inferred mineral resources are that part of the mineral resource for which quantity and grade or quality are estimated on the basis of limited geologic evidence and sampling, which is sufficient to imply but not verify grade or quality continuity. Inferred mineral resources may not be converted to mineral reserves. It is reasonably expected, though not guaranteed, that the majority of Inferred mineral resources could be upgraded to Indicated mineral resources with continued exploration. Mineral resources are captured within an optimized pit shell and meet the test of reasonable prospects for economic extraction.
Metallurgy: Soluble Copper Mineralization
Several programmes of metallurgical testing on Escalones mineralization were completed between 2012 and 2013. Tests focused on the recovery of the copper, gold, silver, molybdenum and gallium by conventional flotation and a combination of flotation followed by acid and acid-brine leaching of sulphide tailings and oxide scavenger concentrates. There was no specific programme to determine the extend of acid-soluble copper mineralization over the full range of mineral zones and rock types.
The standard sulfuric acid leach metallurgical tests achieved average copper extraction of 77%, ranging from 66 to 96% from mixed copper oxide-sulfide mineralization (eight composite samples). Copper sulphide flotation was also successful and rougher-cleaner flotation testing of the porphyry material achieved 25-34% copper concentrate grades at high recovery and low findings of all key impurities.
Recent studies by World Copper indicate that most of the shallow copper mineralization at Escalones could be amenable to heap leach processing, which would result in lower operating costs as well as significantly lower capital costs. The sulphide copper mineralization is partially to completely replaced and enriched from surface to depths of approximately 300m from surface by secondary copper oxides, sulphates and carbonates, resulting in higher grades at shallower depths. The base of oxidized copper enrichment is currently defined by a database review of core photos, assays and core logs, and supported by almost 1200 sequential copper leach tests, representing 2040 metres of core, or roughly 16% of all oxidized intervals. In addition, 55 acid consumption tests were completed. the visual down-hole limits of oxidized and secondary copper sulphide minerals.
Bottle roll leach tests will be undertaken to confirm the positive preliminary findings.
The Escalones deposit remains open to expansion laterally and down dip, with only roughly half of the alteration zone drilled to date. The unexplored Mancha Amarilla lithocap (“Mancha Amarilla”) extends one kilometre south from the main Escalones deposit. Evidence indicates this southern half of the Escalones alteration system is also deeply oxidized and could contain significant soluble copper mineralization. Geophysical and geochemical anomalies indicate there is also substantial expansion potential to skarn zones on both east and west flanks of the porphyry mineralization.
The Escalones Project contains what may be one of the last remaining untested mineralized porphyry clusters in Chile; no drilling has been carried out on these distal targets. Three significant hydrothermal alteration zones, each measuring between 2,000m and 3,000m in diameter, lie 5-10km to the north of the main discovery, and were recce mapped and sampled by General Minerals Corporation (“GMC”) in 1999. GMC discovered disseminated and fracture-controlled copper-oxide and sulphide mineralization within the Rio Negro target, with continuous-chip samples of outcrop returning highly encouraging initial results including 1m of 8.3% Cu, 2m of 0.52% Cu and, 500m to the southeast, 3m of 1.93% Cu within a broader sample of 34m of 0.4% Cu.
A qualified person has not done sufficient work to independently verify these historical sampling results and World Copper does not consider them current or necessarily indicative of future results. The potential quantity and grade of such results is conceptual in nature, there has been insufficient exploration to define a mineral resource and it is uncertain that further exploration will result in such targets being delineated as mineral resources.
A geochemical sampling and mapping crew was mobilized in late February 2021 to evaluate these porphyry copper targets. The ongoing focus of this exploration will be to sample, map and conduct geophysics on the three anomalies in order to optimize drill targets. Preliminary results from initial efforts at the Rio Negro target indicate widespread porphyry-copper style alteration and mineralization.
Results of this current exploration program will be released as information becomes available.
Panorama looking south over northern target cluster.
Rio Negro Target; north side looking northwest over quartz-sericite altered porphyry intrusions.
Arguelles Target: looking south over main colour anomaly.
Cautionary Note Regarding Forward-Looking Statements
Forward Looking Information: this webpage and linked content includes certain information that may be deemed “forward looking information”. Forward-looking information can generally be identified by the use of forward-looking terminology such as “may”, “will”, “expect”, “intend”, “estimate”, “anticipate”, “believe”, “continue”, “plans” or similar terminology. All information in this release, other than information of historical facts, including, without limitation, the potential of the general future plans and objectives for the Escalones project, the completion of the Plan and receipt of shareholder and regulatory approval therefor, the likelihood of receipt of value from the Retained Right, the availability of financing to World Copper Ltd. (“the Company”) and the Company’s plan in relation to its listing review are forward-looking information that involve various risks and uncertainties. Although the Company believes that the expectations expressed in such forward-looking information are based on reasonable assumptions, such expectations are not guarantees of future performance and actual results or developments may differ materially from those in the forward-looking information. Forward-looking information is based on a number of material factors and assumptions. Factors that could cause actual results to differ materially from the forward-looking information include changes in project parameters as plans continue to be refined, future metal prices, availability of capital and financing on acceptable terms, general economic, market or business conditions, regulatory changes, delays in receiving approvals, and other risks detailed herein and from time to time in the filings made by the Company with securities regulatory authorities in Canada. Mineral exploration and development of mines is an inherently risky business. Accordingly, actual events may differ materially from those projected in the forward-looking information. For more information on the Company and the risks and challenges of our business, investors should review our continuous disclosure filings which are available at www.sedar.com. Readers are cautioned not to place undue reliance on forward-looking information. The Company does not undertake to update any forward looking information, except in accordance with applicable securities law.
John Drobe P.Geo., World Copper's Exploration Manager, and a qualified person as defined by National Instrument 43-101, has reviewed the technical information that forms the basis for this webpage.