In August 2021, Freeport Resources Inc. completed the acquisition of Carpo Resources Inc. by acquiring all of the outstanding share capital from the vendors. Carpo is a privately held company that controls Era Resources Inc., which itself controls an application for the renewal of an exploration license located in Papua New Guinea, commonly known as the “Yandera Copper Project”.
Era Resources Inc. is a mineral resources company focused on the development of its flagship Yandera Copper Project. Era owns 100% of Yandera Mining Company Limited (YMCL) registered in Papua New Guinea (PNG); YMCL owns 100% of the Yandera Copper Project.
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Summary:
In general, terms, the mineral system could be classified as a porphyry copper deposit. The system has many of the characteristics of a typical porphyry system, including an association with porphyritic phases of dioritic to granodioritic intrusive phases and typical alteration assemblages associated with potassic, phyllic and propylitic altered rocks. However, there are some key differences between Yandera and typical zoned porphyry systems, including strong structural controls on mineralization and an association between phyllic alteration and elevated copper grades.
The porphyry system at Yandera is hosted in late intrusive phases and structures that disrupt the Bismarck granodiorite. Mineralization appears locally controlled by porphyritic dacite and associated intrusive breccia bodies. The occurrence of these intrusive bodies and later alteration appears to be controlled by a strong northwest trend that intersects and/or is intersected by north and northeasterly trends. Higher-grade copper mineralization appears to be concentrated near the intersection of these trends, such as at Imbruminda, within broader zones of potassic and phyllic alteration.
A number of younger igneous units, including a later porphyritic quartz diorite (POK), porphyritic dacite (PDA), andesite (PAN), microdiorite (POM), and some leucocratic quartz diorite (PLQ), intrude the volumetrically larger quartz diorite porphyry (POD) phases at the property. The younger igneous phases are generally tabular in geometry, sub-vertical, and likely reflect structural zones that were important at the time of emplacement of each.
Within and around the large bodies of POD there are domains of porphyry-style alteration. Within a broad envelope of propylitic alteration, there are more limited domains of potassic alteration and phyllic alteration. Domains of phyllic alteration commonly envelope structures as well as some of the younger intrusive units within domains of potassic and even propylitic alteration.
In association with some of these intrusive units, particularly the porphyritic dacite, there are localized hydrothermal or intrusive breccias. These breccias are commonly closely associated with zones of phyllic alteration. Tectonic breccias observed at the property commonly appear very planar, and sometimes have envelopes of phyllic alteration.
While there is a prominent northwest striking structural trend (300°), there are several other important structural trends including a prominent north-north-westerly trend (330° to 360°) and a north-easterly trend (030°). The northwest trend appears to be the oldest of the three, and reflects the regional-scale structural grain. The north-north-westerly trend cuts the northwesterly trend in a number of locations, but there are some instances when the northwest trend offsets the north-north-westerly trend. The northeast trend appears to be one of the youngest trends, and a number of veins and fractures throughout the property, as well as some prominent sub-vertical dikes of PLQ reflect it.
Early in the copper mineralization history, there likely were some more typical porphyry-style mineralization events with better mineralization associated with potassically altered cores. However, younger, structurally controlled mineralizing events cut these older systems with phyllic alteration that enhanced zones of copper mineralization locally.
Mineralization is most commonly hosted in breccias, porphyritic dacite, porphyritic microdiorite, quartz diorite porphyry and, less commonly, the granodiorite host. Recent interpretive geologic work suggests that higher-grade copper mineralization is commonly associated with phyllic alteration in association with breccias likely related to emplacement of porphyritic dacite.
The most common sulphide minerals in mineralized domains are pyrite, chalcopyrite, bornite and molybdenite, with varying abundances between prospect areas. For example, bornite is more prominent in the Imbruminda area while chalcopyrite is by far the dominant copper mineral at Omora. Previous investigations have interpreted these changes as evidence of typical zonation in a porphyry system; however, some of these differences may alternatively be explained as structural blocks that have been up-thrown or down-thrown to expose different portions of the mineralized system.
Recent work suggests that large-scale structure is very important to controls for mineralization. Mineralization at Gremi and Dimbi roughly follow a northwest trend; however, higher-grade copper mineralization at Imbruminda is coincident with the intersection of a mineralized north- north-westerly trend and a mineralized northwesterly trend.
Analysis of structural data from oriented core indicates that the largest population of veins, dominantly mineralized in the resource area strike northeasterly and dip steeply (~70°+) to the south-east or north-west. The orientation of these veins is sub-parallel to the most populous drill azimuth in the property. Locally, such as at Rima, mineralized veins and veinlets strike nearly north north westerly and dip steeply (77°+) to the west.
Most of the known copper mineralization is hypogene, and near-surface sulphides have been oxidized to varying depths and degrees. For example, oxide mineralization at Gremi reaches depths of up to 50m, while oxide mineralization at Dimbi is significantly shallower. To date, no significant supergene enrichment blanket has been identified at the property.