Marimaca/Ivan Operation

Location Map


The Marimaca copper oxide project, located in the II Region of northern Chile, close to the coast and major infrastructure, is a 1-hour drive north of the port of Antofagasta and 22km from the port of Mejillones. It is 14km from the Antofagasta to Tocopilla via paved highwa (UTS coordinates: UTS 374,800 E and 7,434,900-N). Coro is in the process of acquiring a 75% interest in Marimaca from a local Chilean private company, SCM Compañia Minera Constanza (“Constanza”).

While no drilling had been done previous to Coro’s interest in this property, broad zones of copper oxide mineralization, well-exposed on the hillside, were apparent on the property and were being mined by local artisanal miners via open pit methods when this property came to Coro’s attention. Coro’s experienced exploration team believed that this property would provide a significant and low risk target that met the Coro criteria - a viable leachable copper oxide resource which could be rapidly defined at in an excellent location, all of which would ensure there limited impediments to its expeditious development.

In 2017, Coro completed the acquisition of the Ivan SXEW (Solvent Extraction Electrowinning) plant with a capacity to produce 10,000 tonne per year of copper cathode, which will process ore from the Marimaca copper oxide project.


In August 2014, Coro signed non-binding Letter of Intent to acquire Minera Rayrock Ltda a Chilean subsidiary of Compañía Minera Milpo S.A.A., a Peruvian mining company. Rayrock owned the Ivan SXEW plant located 18km south of Marimaca which has an installed capacity of 10,000 tonnes (22,046,230 lbs) per year copper cathode. This plant operated from 1995 until 2012, at which time it was put on care and maintenance. The Ivan plant’s associated water rights and environmental & operating permits, some of which require updating, were included in the purchase agreement. Through the Rayrock acquisition, Coro also acquired 38,283 hectares (95,000 acres) of mineral claims on which Milpo retains a 2% net smelter return (NSR). Coro acquired Rayrock for a total consideration of US$6.4 million plus an existing closure obligation of approximately US $4.5 million.

In August 2016, following a 60-drill hole exploration program, Coro announced the new discovery at Marimaca. No previous exploration drilling had been done on on this property.

Maiden resource estimate for Marimaca was confirmed in January 2017.


Coro has the right to earn a 75% interest in the property as follows:

  • 51% interest earned with a $125k payment together with completion of a NI43-101 resource estimate and engineering study that demonstrates the technical and economic feasibility of producing a minimum of 1.5ktpy Cu cathode by August 6th 2018 at Coro’s cost. An additional 24% interest may be earned by Coro upon obtaining financing for the project construction
  • The owner’s interest will comprise a 15% interest free carried to commencement of commercial production and a 10% participating interest subject to dilution. The owners at their election may request Coro to loan them the equity portion corresponding to their 10% interest, if any, recoverable by Coro from 100% of the project’s free cash flow after debt repayments
  • Coro retains a first right of refusal


A maiden mineral resource estimate (NI43-101 compliant), was completed by NCL Ingeniería y Construcción S.A., Chile for Marimaca in late 2016 and released in January 2017. Report for the Marimaca Copper Project, Antofagasta Province, Region II Chile, filed 24 February 2017, file size 5,972k

MeasuredIndicatedMeas + IndInferred
Cut Offt x 1000%CuT%CuSt x 1000%CuT%CuSt x 1000%CuT%CuSt x 1000%CuT%CuS

(Note: CuT refers to total copper and CuS refers to acid soluble copper. Cut off expressed in %CuT.)

Only leachable oxides and mixed material were included in estimate with enriched and primary sulphide material present but not included in estimate. Drilling indicated that the deposit remains open in 3 directions. Approximately 20,000,000 tonnes of potential leachable mineralization was also identified but not included in any resource category at this time.
A pit-constrained resource was also calculated within the maiden resource estimate. At a $3.20/lb long term copper price, the following heap leachable pit constrained resources were estimated:

CategoryTonnes% CuT% CuSt CuTt CuS
Measured & Indicated21,499,0000.680.51145,500110,400
Waste54,436,000Strip ratio of 1.31:1

Economic ParametersMining Cost$2.8/t
HL Processing Cost, inc G&A$10.5/t
ROM Processing Cost inc G&A$4.6/t
Selling Cost$0.07/lb
Heap Leach Recovery76% of CuT
ROM Recovery38% of CuT
Pit Slope Angle45o

Sergio Rivera, Vice President of Exploration, Coro Mining Corp, a geologist with more than 32 years of experience and a member of the Colegio de Geologos de Chile and of the Instituto de Ingenieros de Minas de Chile, was responsible for the design and execution of the exploration program and is the Qualified Person for the purposes of NI 43-101. Alan Stephens, FIMMM, President and CEO, of Coro Mining Corp, a geologist with more than 40 years of experience, and a Qualified Person for the purposes of NI 43-101, is responsible for the contents of this website page.

For full technical information on Marimaca, please click here (LINK to Technical Report on Sedar) to view the “Technical Report for the Marimaca Copper Project, Antofagasta Province, Region II, Chile” filed on February 24, 2017.


Marimaca is located in a belt of Mesozoic age copper deposits known as the Coastal Copper Belt, which range in (pre-mining) size from Mantos Blancos at approximately 500 million tonnes of copper to Ivan at roughly 50 million tonnes of copper. They occur in a variety of host rocks and have differing morphologies, but have a common Cu-Ag primary mineralogy zoned from bornite outwards to chalcopyrite and pyrite, deep oxidation and frequently, secondary enrichment.

Marimaca comprises an early stage copper oxide prospect hosted by Jurassic intrusive rocks. Mineralization is controlled by a NNE oriented major structure, representing the northern extension of the same structure that hosts Milpo’s past producing Zar and Emperatriz mines, located 12km to the south. Marimaca mineralization is located within a 500m x 150m cymoid loop, is currently being exploited in a series of open pits over a vertical elevation difference of approximately 150m by mechanized artisanal miners, and has potential to host 10-20 million tonnes of oxides at 0.5-0.8%CuT. Further tonnage potential exists in the underlying primary sulphides.

Photo Gallery

April 2017

Former Ivan leach pads
Surrounding Ivan plant
Ivan operation
Ivan operations landscape
Spent open pit at Ivan
Machinery at Ivan has been on care and maintenance since 2012
Tanks at Ivan plant
Overlooking the solution pumping facility
Overlooking the former ponds and pads at Ivan
Coro board of directors tour of the Ivan facilities
Part of the former pumping facilities to bring solution from the leach pads to the processing plant
VP Exploration, Sergio Rivera explaining the geological structure of the Marimaca property (centre)
Roadside geology lesson for the directors and management team
Board & management at the upper reaches of the Marimaca property looking to the north
Collared drill hole at Marimaca, dipping to the northwest, photo looking toward the ocean, 20km to the west
A series of dirt roads wind through the Marimaca property
Looking to the west from approximately 700 metre elevation at Marimaca
Core stored at the exploration encampment at Marimaca
CEO Alan Stephens offering details of the drill program at Marimaca from which the maiden resource estimate was calculated.
Brochantite and chrysocolla constitute much of the enriched oxidization



Figure 1: Marimaca Looking NW East Sector
Figure 2: Marimaca Looking E East Sector
Figure 3: Marimaca Looking NE West Sector
Figure 4: Sept 2016 Drilling (MAD-01)
Figure 5: Copper oxidation near Drill Hole MAR-19