Mineralization at Santo Domingo occurs primarily as iron oxide–copper–gold (IOCG) deposits with related vein and skarn bodies.

To date, four deposits, three of which support the 2014 Feasibility Study, and a number of prospects have been identified in the Project area.

Santo Domingo Sur
The andesitic flows and tuffs are the primary host to mineralization at Santo Domingo Sur. Mineralization consists of thick semi-massive to massive iron oxide mantos that have replaced the tuffaceous rocks. The stratigraphic sequence of andesitic flows and tuffs dips gently (at an angle of approximately 15°) towards the north–northwest under gravel cover.

Mineralization occurs in the form of copper-bearing semi-massive to massive iron oxide mantos with minor veins and breccias. The mantos are zoned from an outer rim of specular hematite toward a magnetite-rich core.

Drilling has identified a 150 m to 500 m thick, copper-bearing, specularite–magnetite sequence covering an area of approximately 1,300 m by 800 m, and traced to a depth of approximately 525 m below surface. Mineralization consists of stacked chalcopyrite bearing, specularite-magnetite mantos within tuff and tuffaceous sediments overlain by andesitic flows.

The mantos consist of semi-massive to massive specularite and magnetite layers with clots and stringers of chalcopyrite, that range in thickness from approximately 4 m to 20 m. The upper parts of the manto sequence directly below the overlying andesite flows are frequently oxidized and contain various amounts of copper oxides and chalcocite.

Iris
The Iris deposit is essentially blind, covered by a sequence of Quaternary gravel. The elongated shape of the deposit and textures observed in diamond drill holes indicate that the Iris deposit has formed in a north-northwest striking fault zone that is bounded by a west-dipping fault that can be traced along most of the deposit’s western side. The eastern side of the deposit is bordered by a steeply dipping fault that divides andesitic tuffs on the western side from calcareous sedimentary rocks and limestone to the east.

The Iris deposit footprint, when projected to surface, is approximately 500 m wide, has a strike length of 1,800 m, and has been traced from surface to a depth of approximately 670 m below surface. When the dip and plunge of the zones is considered, the real width of the deposit is of the order of 200 m.

The deposit consists of iron oxide mantos and breccias developed along a north–northwest-striking fault zone. The dominant iron oxide at Iris is hematite and the main copper mineral is chalcopyrite.

There are some old mine workings at the southern end of the deposit where copper oxides such as brochantite and chrysocolla were mined at surface. The oxide mineralization is hosted by a specularite manto that is cut by steeply-dipping structures. The extent of oxide mineralization at surface is approximately 100 m by 60 m.

The Iris Mag zone is located between the Iris deposit and the SDS deposit in a separate structural block. Mineralization in the zone consists of magnetite and chalcopyrite with a very high magnetite content (40% and more) and typically low copper content (approximately 0.1% Cu on average). The host rocks are andesitic flows and andesite breccias with a much smaller tuff component than the other zones. It appears that this part of the deposit has been subject to the initial high temperature magnetite event, but shows little evidence of a later oxidizing overprint that has introduced high copper and gold elsewhere.

Iris Norte
The Iris Norte deposit is located about 600 m to the north of the Iris deposit and is also blind, being entirely covered by a gravel sequence. The deposit is very similar in character to Iris, and occurs on the eastern edge of a pronounced gravity anomaly. The deposit is approximately 500 m wide and has been tested over a strike length of 1,600 m and to a depth of 320 m below surface.

Mineralization is primarily hosted in andesitic flows, which differs to the tuff host at Santo Domingo Sur and Iris. The Iris Norte deposit is also elongated in shape and seems to have formed in a structural zone. The deposit displays a northeasterly strike which is a rotation of approximately 55° clockwise versus the strike of the Iris deposit.

Mineralization consists of mixed magnetite and hematite mantos. The main sulphides in Iris Norte are pyrite and chalcopyrite, with the latter providing the copper content of the deposit. Iris Norte contains a higher proportion of magnetite than the Iris deposit and there are a higher proportion of intrusive rocks.

Estrellita
Estrellita comprises an east-west striking, flat lying to shallow north-dipping tabular body lying approximately 3.5 km northwest of Santo Domingo Sur. Mineralization is interpreted by Capstone geologists to occur at a higher stratigraphic level than Santo Domingo Sur, Iris and Iris Norte, which are hosted in tuff sequences below the level of mineralization at Estrellita. Drilling at Estrellita has shown that the host package of andesitic porphyries and flows has a thickness of up to 200 m. In the Estrellita area this package is underlain by a sequence of volcaniclastics with minor intercalations and interbeds of andesite porphyry, limestone and altered tuff.

Estrellita has been faulted into a series of four blocks which step downwards to the north, with displacement across the faults ranging up to approximately 75 m. The overall footprint of the zone measures 900 m long by 450 m wide and is up to 100 m thick.

The character of mineralization at the Estrellita deposit is a mixture of manto style, iron oxide and structurally-controlled, vein-style mineralization. The central part of the Estrellita deposit consists of a more or less horizontal tabular body of iron oxide manto that appears to have formed at the intersection of a flat-lying and a steeply-dipping set of specularite structures.

Copper mineralization typically consists of copper oxides such as brochantite, chrysocolla, almagre, cuprite, and chalcocite. The oxidized mineralization at surface becomes gradually less oxidized with depth and transitions through a mixed zone of oxides and sulphides into a sulphide zone where the main copper mineral is chalcopyrite.

The Santo Domingo Project will include development of two open pit mines using conventional drilling, blasting, loading with diesel hydraulic shovels, and truck haulage.

The Santo Domingo Project will using Semi-Autogenous Grinding (SAG) and ball milling, with conventional flotation utilizing seawater to produce a copper concentrate. Magnetite iron will be recovered from the copper rougher tailings using Low Intensity Magnetic Separation (LIMS). Copper concentrate produced at the process facility will be trucked to (and stockpiled at) the port. Magnetite concentrate will be thickened on site prior to being pumped via a concentrate pipeline to the port. At the port, the magnetite concentrate will be washed, dewatered and stockpiled. Both the copper and magnetite concentrates will be loaded onto ships for transportation to third-party smelters.