Porphyry Copper Project
Optioned to Mine Discovery Fund Pty Ltd.
Drilling, mapping, sampling, geophysics
- Paleocene age porphyry belt of northern Chile
- Lies at relatively low elevation within 20 km of El Salvador and Portrerillos porphyry copper-molybdenum-gold mines
- Year-round access
- Adjacent townships with a trained mining workforce, nearby roads, power, water grid and an operating mill and smelter
The 7,543 ha Rubi Project is located within the Paleocene age porphyry belt of northern Chile that hosts a number of significant, currently producing, porphyry copper deposits. The Project lies at relatively low elevation (1,900-2,100 m), within 20 km of the El Salvador and Portrerillos porphyry copper-molybdenum-gold mines and with good access to port facilities at Chanaral approximately 80 km to the west.
In a regional context, the Project has a prospective geological setting being centered on the structural intersections of the Domeyko fault system and the Ojos del Salado trans-orogen structural corridor, which is interpreted to have influenced the emplacement of the nearby El Salvador and Potrerillos deposits.
DEFINITIVE OPTION AGREEMENT
On October 15, 2020, Mirasol announced that it signed a definitive option agreement with Mine Discovery Fund Pty Ltd. (MDF) for its Rubi project.
Mirasol granted MDF the option to earn-in 80% of the project over eight years by delivering a positive NI 43-101 compliant Prefeasibility Study Report. MDF has committed to funding a 2,000 m drill program at Rubi. Following the completion of this initial commitment, MDF is required to spend a minimum of US$1 million per year in exploration expenditures over the term of the agreement.
MDF is fully funded to complete the committed 2,000m drill program at the project. Mirasol will be the operator during the option period.
Following the completion of the 80% earn-in, MDF will have a one-time option to acquire the remaining 20% interest on terms to be negotiated between the parties. If this option is not exercised, the parties will form a participating joint venture to further fund the development of the Project.
If either party’s interest in the joint venture is diluted to 10% or below, it will convert to a 1.5 % net smelter returns (“NSR”) royalty. The non-diluting partner can buy back 0.5% of the NSR royalty for the fair market value as determined by a qualified independent valuator.
Mirasol has completed field evaluation and targeting programs at Rubi identifying two large-scale copper, molybdenum and gold targets at the Lithocap and Zafiro prospects.
The Rubi Lithocap target (“Lithocap”) covers a 3.5 km by 2.0 km area centred on a large, deeply weathered, advanced argillic alteration zone that is surrounded by gravel cover with thicknesses modelled from a gravity survey of 10-50 m. Large and productive porphyry copper deposits can be found below or adjacent to the type of lithocap alteration zones present at Rubi.
At Lithocap, previous explorers have drilled peripheral to, but not beneath or adjacent to, the post-mineral gravel covered western edge of the copper and locally strong Mo anomaly. Mirasol’s mapping and re-logging of previous drill holes have defined veining and brecciation with anomalous copper and molybdenum mineralization and alteration patterns that indicate potential concealed porphyry mineralization to the north and north-west of the previous drill holes.
This combined information suggests the presence of a deep weathering profile that could potentially overlie supergene enriched and sulfide mineralization, as indicated by an Induced Polarization geophysical chargeability anomaly, which remains open to the north. This type of deep weathering in porphyry environments in northern Chile is often conducive for the development of supergene enriched copper mineralization akin to the nearby El Salvador mining district.
The Zafiro target (“Zafiro”) features a 2.8 km by 2.2 km gravel covered area characterized by a subtle circular magnetic high surrounded by an incomplete, doughnut-shaped magnetic low. This magnetic signature may be indicative of a large gravel-covered intrusive with a pyritic alteration halo. The gravel cover in this area ranges from approximately 25 m to more than 200 m in thickness concealing the central target area. However, a large canyon 1 km to the north of the target cuts through the gravel profile exposing the basement rock. Mirasol’s stream sediment sampling of gullies, located immediately north/northwest of the Zafiro target, have returned widespread and strongly anomalous copper over 2,400 m with multiple results in the 500 ppm to 1,530 ppm range, suggesting either an “exotic” source of copper in the gravels and/or a primary porphyry source for the copper in the gravel-covered basement.
High grade “exotic” copper or a supergene enriched porphyry are both attractive exploration targets at Zafiro. Significant ore bodies of these types of mineralization occur at the nearby El Salvador mining district.
Previous Exploration Work
Between 2007 and 2012, Mirasol has completed reconnaissance exploration including stream and rock geochemical sampling, regional mapping and PIMA analysis of the prospect area. The exploration work enabled Mirasol to identify the initial Lithocap prospect.
Under a partnership with Mirasol, First Quantum Minerals (FQM) completed multiple exploration programs between 2013 and 2015 to further explore Rubi project. The programs include a 2,460 line-km, detailed, low-altitude, helicopter-borne magnetic (helimag) survey covering the entire Rubi project, property-wide geological mapping and rock chip sampling, and orientation soil sampling was also completed at the Lithocap prospect. A 6,054 m, 16-hole combined reverse-circulation and diamond drill program predominantly focused in the Lithocap area was also completed in 2015.
In 2017, Mirasol consolidated its claims holdings at Rubi and completed field evaluation and targeting programs that refined three large-scale Cu-Mo-Au targets at the Lithocap and Zafiro prospects. The targets were defined by integrated analysis, including re-logging of drill holes and the re-interpretation of geophysics and geochemistry from previous partner exploration work at Rubi.
- October 15, 2020Mirasol Resources Options Rubi Copper Project in Chile to Mine Discovery Fund
July 24, 2017Mirasol Resources Defines Three Porphyry Copper Targets at 100% Owned Rubi Project, Northern Chile
April 2, 2015Mirasol reports that First Quantum Minerals has relinquished its option over the Rubi project in Northern Chile
November 10, 2014Mirasol reports geophysical results and the start of drilling at the Rubi JV with First Quantum in northern Chile
September 3, 2014Mirasol provides exploration update on Rubi copper-gold porphyry JV with First Quantum Minerals in Northern Chile
August 27, 2014Mirasol and First Quantum Minerals sign Definitive Exploration Option and Joint Venture Agreement for the Rubi Property, Chile
February 24, 2014Mirasol Provides Update on Aggressive Exploration Program on the Rubi copper-gold JV Project in Northern Chile