The Camino Rojo property is 100% owned by Orla Mining Ltd. through its Mexican subsidiary Minera Camino Rojo S.A. de C.V.
Orla is the operator of the Camino Rojo Project and has full rights to explore, evaluate, and exploit the property. Pursuant to the option agreement dated November 7, 2017 between Newmont and the Company, if a sulphide project is defined through a positive Pre-Feasibility Study outlining one of the development scenarios A or B, Newmont may, at its option, enter into a joint venture for the purpose of future exploration, advancement, construction, and exploitation of the sulphide project.
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Summary:
The Camino Rojo Project deposit is located beneath a broad pediment of Tertiary and Quaternary alluvium along the boundary between the Mesa Central physiographic province and the Sierra Madre Oriental fold and thrust belt near the pre-Laramide continental-margin.
On the Camino Rojo Project, a gold-silver-zinc-lead deposit lies concealed below shallow (<1 m to 3 m) alluvial cover in a large pediment along the southwest border of the Sierra Madre Oriental. Small water storage pits and trenches expose a portion of the oxide deposit in the discovery area known as Represa zone. The Late Cretaceous Caracol Formation is the primary mineralization host, and at depth, the upper Indidura Formation is a minor mineralization host along the Caracol contact. The gold-silver-lead-zinc deposit is situated above, and extends down into, a zone of feldspathic hornfels developed in the sedimentary strata, and variably mineralized dacitic dikes. The mineralized zones correspond to zones of sheeted sulfidic veins and veinlet networks, creating a bulk-mineable style of gold mineralization. Skarn mineralization has been encountered in the deeper portions of the system.
Mineralized Zones
The Camino Rojo deposit comprises intrusive related, clastic sedimentary strata hosted polymetallic gold, silver, arsenic, zinc, and lead mineralization.
Three stages of mineralization, including two styles of high-grade gold-silver mineralization, have been observed in the Camino Rojo deposit:
• Stage 1 K-metasomatism (adularia)-pyrite – K-metasomatism with disseminated pyrite replaced the mudstone, siltstone and fine-grained sandstones in the Caracol Formation. Mineralization is typically low-grade gold with 0.1- 0.4 g/t.
• Stage 2 Intermediate Sulphidation (“IS”) veins – IS veins with pyrite-arsenopyrite-sphalerite±galena, calcite and minor quartz. Moderate to high grade gold (0.4 to +4.0 g/t), high zinc grades (0.5 to >2.0% Zn) and high values of As, Pb and Ba, with variable Ag.
• Stage 3 LS veins – colloform banded quartz veins, drusy-coxcomb quartz veins, and quartz-cemented, polymictic hydrothermal breccia with pyrite-galena-sulphosalts, adularia and electrum. Moderate to high gold grades (2.0 to 15.0 g/t) with high silver (100 to 500 g/t), and high As and Sb values, but variable to low Zn, Pb, and Ba values.
At hand specimen scale, mineralization is controlled by bedding and fractures. The sandy and silty beds of the turbidite sequences of the Caracol Formation are preferentially mineralized, with pyrite disseminations and semi-massive stringers hosted within them, presumably due to higher syn-mineralizing fluid porosity and permeability relative to the enclosing shale beds. Basal layers of the turbiditic sandstone beds are often preferentially mineralized. Bedding discordant open space filling fractures and structurally controlled breccia zones host banded sulphide veins and sulphide matrix breccias. Some higher-grade vein and breccia zones are localized along the margins of dikes of intermediate composition. Gold-silver mineralization has been observed in drill core over vertical intervals greater than 400 m, with gold-silver mineralization occurring in a broad NE-SW trending elongate zone as much as 300 m wide and 700 m long.
Oxidation was observed to range from complete oxidation in the uppermost portions of the deposit, generally underlain or surrounded by a zone of mixed oxide and sulphide mineralization where oxidation is complete along fracture zones and within permeable strata, but lacking in the remainder of the rock, which then is generally underlain by a sulphide zone in which no oxidation is observed. Oxidation of the deposit is approximately 100%, generally extending from surface to depths of 100 m to 150 m and to depths of as much as 400 m along fracture zones. The underlying transitional zone of mixed oxide/sulphide extends over a vertical interval in excess of 100 m and is characterized by partial oxidation controlled by bedding and fractures. The sandy layers of the turbiditic sequence are preferentially oxidized, creating a stratigraphically interlayered sequence of oxide and sulphide material at the centimetre-scale, with oxidation along structures affecting all strata. Gold bearing strata of the of the Caracol Formation are preferentially oxidized and auriferous zones range from partially to completely oxidized, thus the metallurgical characteristics of mixed oxide/sulphide may vary greatly, with some material exhibiting characteristics similar to oxide material.
The 2021 Camino Rojo Report concludes that the distribution of mineralization at Camino Rojo is controlled by both primary bedding and discordant open space filling structures. Pervasive, near surface oxidation extends to depths in excess of 100 m and extends to greater depths along structurally controlled zones of fracturing and permeability.
Deposit Types
The observed geologic and geochemical characteristics of the gold-silver-lead-zinc deposit are consistent with those of a distal oxidized gold skarn deposit. The near surface portion of the Camino Rojo deposit has characteristics consistent with those of the distal skarn zone, transitional to epithermal mineralization, and overlies garnet bearing skarn mineralization encountered in the deeper portions of the system. Skarn deposits often exhibit predictable patterns of mineral zoning and metal zoning. Application of skarn zoning models to exploration allows for inferences about the possible lateral and depth extents of the mineralized system at the Camino Rojo deposit and can be used to guide further exploration drill programs.