The Eagle Mountain Project is operated by Stronghold Guyana Inc., a wholly-owned subsidiary of Goldsource Mines Inc.
On July 3, 2024, Mako Mining Corp. completed its previously announced acquisition of Goldsource Mines Inc. by way of a plan of arrangement, pursuant to which Mako acquired all of the issued and outstanding common shares of Goldsource in exchange for common shares of Mako. As a result of the Transaction, Mako now owns the Eagle Mountain Gold Project in Guyana.
- subscription is required.
Summary:
The main style of gold mineralization on the Eagle Mountain Property is related to a series of tabular, shallow southwest-dipping, brittle-ductile composite deformation zones within a granodiorite intrusion (Eagle Mountain deposit), or within upright breccia structures within mafic volcanics and altered granitoids (Salbora deposit). Gold mineralization is associated with silicification and with chloritic ± pyritic alteration. Alteration and sulphide mineralization within the low-angle structures is interpreted to be syn-deformational, and the similarity of alteration types at Eagle Mountain and Salbora suggest that they are part of a single mineralized system.
Both the Eagle Mountain and Salbora deposits are considered to be an orogenic-type gold system, also known as lode-gold deposits or (in the case of Archean and Paleoproterozoic deposits) greenstone hosted quartz-carbonate vein deposits.
Mineralization
Mineralization at both the Eagle Mountain and Salbora deposits is structurally controlled and related to shallow-dipping fault zones and steep to near vertically dipping faults and breccia zones, respectively.
Gold at both Eagle Mountain and Salbora occurs as native gold, as very fine disseminations associated with and contained in pyrite. This pyrite is typically associated with chlorite alteration or chlorite veins. An exception is rare visible gold within an interpreted early generation of quartz veins that have been subsequently deformed. This represents an earlier stage of gold mineralization than the main mineralization event. A separate episode of molybdenum mineralization associated with quartz veining is also locally noted within the Eagle Mountain Gold Project.
Although the orientation of the controlling structures is different, both the Eagle Mountain and Salbora deposits show an association of gold with quartz-chlorite-pyrite alteration, and at both deposits these syn-mineralization alteration assemblages are overprinted by brittle carbonate veins. These veins crosscut mineralization and represent late-stage fluids. The similarity of the alteration assemblages suggests that both deposits formed as part of a single mineralizing system.
Eagle mountain.
Eagle Mountain
At the Eagle Mountain deposit, gold mineralization occurs in granite as disseminated zones ranging from 1 to 40 metres in thickness. Zones are controlled by a stacked series of low-angle southwest dipping faults related structures. Mineralization is not strictly localized in these fault structures. Very often, the highest gold grades are found within or close to the main fault zone where the alteration is intense with a high density of small fractures containing chlorite and pyrite. The mineralized zones are separated by 10 to 100 metres of granite.
The Eagle Mountain deposit is modeled as a series of tabular, sub-horizontal to shallowly dipping zones.
• Uppermost Zones 1 and 2 host most of the gold mineralization at the Eagle Mountain deposit and typically extend from outcrop to 20 metres deep, and up to 80 metres deep in areas of high elevation (e.g., the Saddle target). Zone 1 outcrops at the Zion, Ounce Hill, Bucket and Bacchus deposit areas. Zone 2 outcrops at the Killroy area. Both zones extend north-eastward at increasing depth below topography.
• Two additional zones (Zone 3 and the more substantive Zone 4), both stratigraphically below Zone 2, extend north-eastward from outcrops at the Baboon, Bottle and Friendly areas.
• Zones 5 to 10 are encountered at the Powis deposit which displays characteristics of shallowly dipping mineralized zones with higher-grade quartz veins, and at the Toucan prospect located at the western extents on the Eagle Mountain deposit.
• These zones extend westward to depths of 80 metres in the Friendly at Bacchus areas and dip toward the south with depths increasing to a maximum of 150 metres in the Baboon deposit areas. Mineralization at the Powis target also occurs in small discrete “cloudy” veins, often showing visible gold, and preferentially developed in a quartz porphyry granitoid, and is thought to be a separate stage of mineralization to the main Eagle Mountain deposit.
• At Toucan, a Salbora-style steeply dipping mineralization is encountered with increased silicification and mineralized breccias.
• Eagle Mountain mineralized zones have been defined on the basis of alteration, grade and identification of structures, and the variable thickness of each of the mineralized zones appears to be related to whether a single deformation zone occurs or whether it zone splits into several sub-parallel zones, thereby broadening the zone of alteration and mineralization.
Salbora
At the Salbora deposit, gold mineralization occurs within and adjacent to sub-vertical, north-south trending breccia zones that are generally a few cm to a few metres in thickness. Near the surface, these breccia zones appear to coalesce into broad, sub-horizontal zones of brecciation with mineralization occurring over tens of metres. Breccias are developed in a tholeiitic mafic volcanic and altered granitoid adjacent to a monzonite intrusion. Mineralization is associated with silicification, chloritic alteration and pyrite. Multi-element geochemistry indicates that gold is associated with minor concentrations of silver and arsenic.
Target areas
The Montgomery target lies north of Salbora, and mineralization is associated with chlorite + silica + pyrite filled breccia zones in granitoid rocks near the contact between mafic and granitoid units. Breccias are also developed in mafic units but appear to be less mineralized.
The Soca target lies to the south of Ann, along the north-south alignment. Mineralization at Soca is within silica and chlorite alteration of a quartz porphyry granitoid and its margins into granodiorite. Small breccias occur, but the primary mineralization is alteration hosted. Soca was not considered for the MRE.
The Soca-Ann-Toucan-Powis-Salbora-Montgomery targets form in a north-south alignment, interpreted to represent a large-scale, north-south trending zone of deformation and mineralization. The kinematics and orientation of this deformation zone are not yet clearly understood.
Weathering and oxidation – saprolite mineralization
Saprolite is the chemical weathering product of the underlying bedrock that has decomposed in place and generally retains the rock’s original structure and is especially characteristic of tropical lateritic weathering profile. The saprolite consists of soft clay to sandy particles, depending on the rock type being weathered and the amount of quartz present. Both the Eagle Mountain and Salbora deposits are affected by weathering that results in a typical saprolite depth of 10 to 30 metres and rarely to a maximum depth of 76 metres from surface. Saprolite transitions to fresh rock across a variable horizon is typically 1 to 3 metres thick.
The vertical and lateral variability within the laterite profile at Eagle Mountain has not been clearly defined. No ferruginous zone has been described and the upper part of the laterite profile may have been removed by erosion.
Saprolite and transition material is both mineralized and unmineralized. Gold mineralization within the saprolite at the Eagle Mountain deposit occurs were mineralized zones reach shallow depths or outcrop. Mineralized saprolite is derived from mineralized granodiorite and consists of clay-rich material with very fine-grained disseminated gold. There is no evidence for gold remobilization or enrichment in the supergene environment. Furthermore, there is no evidence of transportation or slope slip of saprolite.
At Salbora, the shallow mineralized zone has also been affected by weathering, resulting in a zone of mineralized saprolite near the surface.