2742 St. Joseph Blvd., Unit 200
Canada, K1C 1G5
Sunstone Metals (ASX code: STM)
Originally acquired by Cornerstone in 2005, straddles the Gañarin Belt, a 50 km-long regional feature which contains volcanic centres and associated high-level intrusions, that is highly prospective for hosting epithermal gold - silver ± copper and porphyry copper - gold ± molybdenum deposits. Multiple, east-northeast trending low sulphidation epithermal quartz veins and vein breccias have been found measuring from 1.0 to 7.0 m in width within a zone at least 2 km long and 1.5 km wide. Mineralized veins containing gold and silver are exposed over a vertical relief of 300 m with the highest gold values localized at vein intersections and where veins outcrop around the 3,220 m elevation. Channel sampling across surface outcrops has returned 53.4 g/t gold and 641 g/t silver over 3.4 m.
Cornerstone has been exploring in Ecuador since 2005 through its wholly-owned subsidiaries, Cornerstone Ecuador S.A. (CESA) and La Plata Minerales S.A. (PLAMIN). The Company has a portfolio of drill-ready projects in Ecuador targeting epithermal gold-silver and porphyry copper-gold deposits.
An important part of the future valuation of Cornerstone derives from its minority financed interest in the Cascabel copper gold project in northern Ecuador, where drilling is ongoing and where fifteen high-priority porphyry centres are now recognized within the project. On January 3, 2018 the Company and its majority joint venture partner SolGold Plc announced a maiden mineral resource estimate for the Alpala deposit of 430 Mt @ 0.8% Copper Equivalent (CuEq) Indicated and 650 Mt @ 0.6% CuEq Inferred (3.4 Mt CuEq Indicated 4.0 Mt CuEq Inferred) at 0.3% CuEq cut off.* (For more details, see Cascabel page).
Cascabel is located in north-western Ecuador in an under-explored northern section of the richly endowed Andean Copper Belt, 60 km northeast of the undeveloped inferred resource of 982 million tons at 0.89% Cu Junin copper project (0.4% Cu cut-off grade; Micon International Co. Ltd. Technical Report for Ascendant Exploration SA, August 20, 2004, pages 28 & 29). Mineralization identified at the Junin copper project is not necessarily indicative of the mineralization on the Cascabel Property.
On March 6, 2017, Cornerstone announced that its joint venture partner, Ecuador State Mining Company ENAMI EP, had been granted a number of mineral concessions in Imbabura and Carchi provinces in the same area as the Cascabel and the Llurimagua concessions, for exploration by the ENAMI-CESA strategic exploration joint venture. Nine concession titles totaling almost 40,000 hectares were granted in 2017 by the Ministry of Mining (please see ENAMI Strategic Alliance page).
The Company has two wholly-owned exploration projects located in southern Ecuador, the Bella Maria and Vetas Grandes projects, as well as one property, Caña Brava, in which it has the right to earn 100%. The Vetas Grandes gold prospect is strategically located approximately 15 kilometres west of the Loma Larga (formerly called Quimsacocha) high-sulphidation epithermal gold-silver-copper deposit, south of the Rio Blanco low-sulphidation gold-silver deposit and southeast of the Chaucha porphyry copper-molybdenum deposit. On all three projects, the Company has identified sizeable altered and mineralized zones which offer good potential for new discoveries.
The Company also has a joint venture with Sunstone Metals Inc. on the drill-ready Bramaderos property in Loja Province (please see Bramaderos Property page).
Bella Maria is underlain by a series of granodiorites and quartz porphyries that intrude metamorphic rocks. Previous workers identified two zones of significant gold mineralization, approximately 2 km apart. One zone, in the south-central portion of the property, consists of a silica-sulphide breccia that has returned assays averaging 4.5 g/t Au over 40 m from continuous rock chip sampling, including 10.8 g/t Au over 16 m. The second zone occurs 2 km to the northwest and consists of stockwork veins from which grab samples assayed up to 10.8 g/t Au and chip samples returned assays up to 0.54 g/t Au over 6 m. The two zones are separated by an area of thick vegetation and poor exposure with many unexplained geochemical anomalies. Data on the property are being compiled in preparation for initiating further exploration.
Exploraciones Novomining S.A. ("ENSA"), an Ecuadorean company owned by SolGold and Cornerstone, holds 100% of the Cascabel concession. Subject to the satisfaction of certain conditions, including SolGold's fully funding the project through to feasibility, SolGold Plc will own 85% of the equity of ENSA and Cornerstone will own the remaining 15% of ENSA.
The Cascabel property is underlain by Upper Cretaceous sedimentary rocks which are overlain by Oligocene to Miocene andesitic flows and breccias. These units are intruded by Miocene age granodiorite and diorite batholiths and stocks. Major regional tectonic structures in the area strike northeast. One such structure, the Apuela regional fault, transects the southeast part of the Cascabel property. Several mineral prospects which are hosted in the same geological belt, have been identified in the Cascabel district including the Chical (Au-Ag) and Rio Amarillo (Au-Ag-Cu) epithermal prospects located 12 km to the northwest and 12 km to the south of the property respectively. Cascabel is located upstream from an extensive alluvial gold district, Playa de Oro, located 50 km to the west.
Alpala MRE Technical Report
Work on the Shyri concessions, collectively over 450 km2 in area, indicates potential for low and high sulphidation precious metal deposits in several target areas. The Shyri concessions straddle the Gañarin Belt and are immediately adjacent to IAMGold Corporation's Quimsacocha project. The Gañarin Belt is a 50 km long feature with several volcanic centers, related intrusives and numerous epithermal gold-silver prospects. Quimsacocha is the most advanced project in the Gañarin Belt. IAMGOLD first announced significant drill intersections at Quimsacocha in December 2004 and in September 2006 they reported an indicated resource of 3.4 million ounces of gold in the deposit (IAMGold Corporation press release, 27 September 2006).
The Vetas Grandes project covers 107.75 km2 located in the central portion of the Shyri concessions, immediately southwest and contiguous with IAMGold's Quimsacocha project.
This project has two main prospects; the Vetas Grandes prospect and the Tasqui prospect.
The Vetas Grandes prospect has several large, 3.0 m to 7.0 m wide veins and quartz vein/vein breccia/stockwork form a swarm striking east-northeast over a distance of 1.4 km. The veins have elevated mercury (Hg), selenium (Se) and tellurium (Te) and display diagnostic textures indicative of a high level epithermal system with bonanza grades focused at the 3200 m elevation. Extensive surface sampling and geophysical surveys (magnetic and IP) have been completed over the prospect.
The Tasqui Prospect consists of a 2.0 to 7.0 m wide magmatic-hydrothermal vein breccia which has been traced over a distance of 440 m. This was originally discovered by float prospecting that has just recently been traced to outcrop.
Gold and Copper
The Cañar (115.41km2) property comprises of concessions in the Canar province, Southern Ecuador.
These concessions cover a large part of an even larger porphyry Cu-Mo alteration/mineralization system (and associated epithermal mineralization). The individual potassic alteration zone typically covers areas 1-2 km2, within broader halos (3 to 5 km2) of phyllic alteration. Base metal mineralization is associated to quartz veinlets/sotckworks. At Cañar, high grade, high sulfidation type mineralization is associated to vuggy silica structures within an advanced argillic zone.
El Fundo comprises 8.25km2; located in the Loja province.
El Fundo has an unspecified alteration zone measuring 3 to 4 km2. There is a 200 x 50m hydrothermal breccia zone showing massive silica and vuggy silica fragments with associated As, V, Bi, and Te anomalies.
ENAMI Strategic Alliance
On June 14, 2016, the Company announced that its Ecuadorean subsidiary, Cornerstone Ecuador S.A. ("CESA"), had signed a definitive agreement (the "Agreement") with Ecuador's State Mining Company, Empresa Nacional Minera Empresa Pública ("ENAMI"), replacing the letter of intent announced April 14, 2015, and creating a structure to jointly prospect and explore for mineral deposits in Ecuador.
In a First Phase, CESA will identify, at its own cost and risk, geologically prospective areas in parts of Ecuador ("Areas of Interest" or "AOIs"), and identify them to ENAMI, which will make application to the Ministry of Mining ("MM") for a concession or concessions covering such areas (which concession will be granted based on the plans, policies and guidelines of MM for the mining sector). Although ENAMI is a state enterprise, the granting of mineral concessions in Ecuador is within the exclusive jurisdiction of MM, which sets its own policies with regard to the timing of opening certain areas of the country to exploration and to whom mineral concessions will be granted, as a result of which there is no guarantee that concessions requested by ENAMI for joint exploration with CESA & Partner will be granted. Once a concession has been granted, ENAMI and CESA will form a specific purpose corporation (the "SPC"). ENAMI will transfer the concession to the SPC as a capital contribution in return for a 16% shareholding in the SPC. CESA, employing its project generator business model, and a funding partner who will earn a majority interest in the projects (collectively, "CESA & Partner"), the exact percentage to be negotiated with CESA, will prospect the concession to identify the most prospective parts. CESA & Partner will have a collective 84% shareholding.
The First Phase will be subdivided into: (i) Prospecting, with committed expenditures of $5 per hectare within the AOI (e.g., $100,000 per 20,000 hectares), (ii) Initial Exploration (up to 4 years including 18 months of prospecting), with optional expenditures of an additional $600,000; (iii) Advanced Exploration, including drilling (up to 4 years), with optional expenditures of an additional $4.3 million. Expenditures may be accelerated, amounts in excess in any period will be credited to the next succeeding periods, and shortfalls may be paid in cash to maintain the option in good standing. CESA & Partner may abandon their option at any time, except during the prospecting portion of the First Phase where the $5 per hectare expenditures are committed, delivering all technical information to ENAMI and arranging for a re-conveyance of the respective concessions to ENAMI from the SPC. ENAMI will have a "free" carried interest through to completion of a Bankable Feasibility Study, or "BFS".
In a Second Phase, CESA & Partner will fund the SPC to commence Economic Evaluation (e.g., scoping, pre-feasibility and/or feasibility studies) (up to 2 years, renewable for up to an additional 2 years), incurring optional expenditures of an additional $10 million. Total expenditures on each concession (which can by law cover an area up to 5,000 hectares) through completion of a BFS could total a minimum of $15 million - i.e., $100,000 or more in prospecting (assuming an AOI of 20,000 hectares), $600,000 in Initial Exploration, $4.3 million in Advanced Exploration, plus $10 million during Economic Evaluation. In the event CESA & Partner make a Production Decision to construct a mine/mill and related infrastructure, ENAMI will have the option of financing the totality of its own participating interest, or electing to have CESA & Partner finance the totality of ENAMI's interest (including sustaining capital after commercial production is achieved) at cost of funds plus an agreed financing arrangement fee.