Colombia

Anzá is Orosur’s flagship project.

After being acquired by Orosur in 2014, the project saw little work as the Company focussed on its Uruguay operations, but since late 2020, Anzá has transformed into our main asset and one of the more exciting gold projects in the region.

The Anzá project is a JV between Orosur, and two of the worlds largest gold producers in Newmont and Agnico Eagle, and ongoing drilling programs are consistently producing very thick, high grade gold intersections.

Tenure

The Anzá project consists of seven licences (three granted and four applications) totalling approximately 207km2.

Joint Venture Terms

The Anzá project is currently held 100% by Orosur’s Colombian subsidiary, Minera Anzá.

The Project is subject to an “Exploration Agreement with Venture Option” (the Agreement) which was signed in September 2018 with Colombian company Monte Minera Aguila, which is itself a 50:50 JV between Newmont Mining Corporation and Agnico Eagle Mines.

The Agreement is split into three phases:

Phase 1 – a four year option period whereby Minera Monte Aquila must spend $10m in qualifying expenditure on the project and make $2m in option payments to Orosur.

At the end of this stage, should all obligations be met – Minera Monte Aguila would have the right to enter in a formal JV with Minera Anzâ, with an initial 51% equity position. Minera Monte Aguila would be required to make a payment of $2m to Orosur upon its decision to move to Phase 2.

Phase 2 – a four year period over which Minera Monte Aguila can earn an additional 14% equity in the project (bringing its equity position up to 65%) by spending an additional $20m.

Phase 3– a four year period over which Minera Monte Aguila can earn an additional 10% equity by producing a 43-101 definitive feasibility report.

The Anzá project is located in the Western Cordilleran region of Colombia, 50 km west of Medellin (107 km by road) and a few km west of the River Cauca.  

The project lies withing the N-S trending Mid-Cauca belt. 

The Mid-Cauca Belt is defined as a belt of late Miocene porphyry and related deposits hosted in the Romeral melange north west Colombia (Figure. 1).

The primary large-scale driving force for mineralization in this region is the gradual subduction of the Nazca oceanic crust under the continental South American plate at roughly 15cm per year (Figure 2)

As this oceanic crust and its sediment load is subducted, it is remelted, which in turns creates upwellings of volatile magma that has led to the volcanic arc that is the Andes mountain range. This active volcanism is the source of both the metals and the heat to drive the geological processes that ultimately lead to a range of mineral deposits, along, and on either side of the Andes Arc.

The mid-Cauca belt lies to the east of the Andes in a geological setting referred to as a “back-arc” basin and shows a variety of mineralisation styles such as porphyry Cu/Au, epithermal gold and VMS deposits (Figure 3).  While distinctly different in size, grade and chemistry, all of these types of mineralisation share a common origin of a deep-seated intrusion as the source of metals and heat.

Work at Anzá thus far is suggestive of a hybrid VMS/Epithermal gold system, or a situation whereby two temporally distinct mineralizing events occur in the one location.

Both gold and base metal mineralization is concentrated predominantly in a thick, silicified breccia, with minor mineralization extending into the bounding lithologies. The breccia would seem to be structurally controlled with the SSW-NNE trending Aragon fault.

The Anzá Project came under Orosur’s control in June 2014 upon the completion of a Plan of Arrangement between Orosur Mining and TSX.V listed Waymar Resources, that in effect merged the two companies.

Waymar had acquired the project some years before after being spun out from Continental Gold upon its decision to concentrate on the Buritica deposit in Colombia.

Waymar had carried out some significant exploration programs, at Anzá, including some 18,000m of drilling, concentrated on the central APTA deposit, as well as some regional sampling carried out in cooperation with Anglo American.

Post-merger, Orosur then completed several smaller exploration and drilling phases at APTA and Charrascala, for some 6,000m.  However, from 2018, exploration work was wound back as the company focussed on the wind up of its San Gregorio operations in Uruguay.

The existing Joint Venture with Newmont Mining Corporation was signed in September 2018, allowing it a three phased earn-in of up to 75% in Anzá by spending a minimum US$30.0mm over 12 years, completing an NI 43-101 feasibility study & making cash payments to Orosur equalling  US$4.0mm, and by taking a US$2mm equity placement in the company, acquiring 29,213,186 shares.

In October 2020, it was announced that Agnico Eagle Mines Ltd, would join Newmont on a 50:50 basis to share its rights and responsibilities with regard to the Anzá joint venture.

Drilling recommenced on the project in November 2020, after a hiatus of several years.