American Rare Earths

Halleck Creek Project

The Halleck Creek project area, located in Albany County, Wyoming, comprises two main ares: the northern Overton Mountain area and the southern Red Mountain area. The project is owned by Wyoming Rare (USA) Inc., a wholly owned subsidiary of Western Rare Earths, a wholly owned subsidiary of American Rare Earths, Limited (ASX: ARR; OTC: ARRNF). With favorable results from the maiden exploration drilling, American Rare Earths will expand exploration drilling into developing preliminary resource estimates for Halleck Creek. According to a January 2022 report by the Wyoming State Geological Survey, “Wyoming is in a unique position to become a national leader in the development of domestic critical mineral production.”

The greater Halleck Creek Project area consists of 68 unpatented lode claims, covering approximately 1,265 acres (512 has). The company controls six Wyoming State Mineral Leases in the surrounding area, totalling 1,843.72 acres (756 has). The project is located in Albany County, Wyoming, approximately 40 miles north of Laramie, Wyoming.

Initial surface sampling of the Overton Mountain area conducted in 2018 by Zenith Minerals, an Australian Mining Company, revealed average Total Rare Earth Oxide (TREO) values of 3,297 ppm, average Heavy Rare Earth Oxide (HREO) values of 224 ppm, and average Magnetic Rare Earth Oxide (MREO) values of 816 ppm.

In June and July of 2021, a follow-up surface sampling program totalling 197 samples were collected from the Halleck Creek project area with favorable and significant results showing an average Total Rare Earth Oxide (TREO) value of 3,187 ppm and a noteworthy, combined Nd and Pr average of 702 ppm. The results also showed that the Red Mountain Pluton is Light Rare Earth Oxide (LREO) dominant, with an average of 2,836 ppm.

The encompassing Halleck Creek project area is located within the Laramie Anorthosite Complex (LAC). The LAC consists of three major anorthositic intrusions – Chugwater, Poe Mountain, and Snow Creek. These are rimmed by associated mononitic intrusions, including the Sybille intrusion, the Maloin Ranch pluton, and the Red Mountain pluton. The Halleck Creek project area is located within the Red Mountain Pluton (RMP), the youngest and smallest intrusion of the LAC.

Four units comprise the RMP, including a fayalite monzonite (FM), clinopyroxene quartz monzonite (CQM), biotite-hornblende quartz syenite (BHS), and the Red Mountain granite (RMG). Three types of dikes also occur within the pluton, including fine quartz monzonite (FQM), medium quartz monzonite (MQM), and biotite-hornblende monzonite (BHM).

Initial studies have shown there is widespread surface REE mineralization over hundreds of meters, total rare-earth oxide (TREO) up to 0.60% in three initial sampling areas, and a high percentage of high-value Neodymium, Praseodymium, and Dysprosium.

As this Project occurs within the Laramie anorthosite complex – a proterozoic massif consisting of three anorthositic intrusions, three syenitic to monzonitic intrusions, and several smaller intrusions of leucogabbro and ferrodiorite – metallurgy is key to its processing potential. Rare earths occur at the Laramie prospect predominantly as the mineral Allanite hosted by clinopyroxene syenites that are part of a very large, differentiated Laramie anorthosite complex.

Allanite is coarse-grained (0.4mm to 2.5mm) as distinct mineral grains. DCM reported that “the large size of the allanite crystals should facilitate liberation upon grinding” from the syenite host rock. As such, mineral separation by magnetic (high REE content) as well as by gravity (very low REE content) methods have been tested, with 87% of the REE minerals being recovered into 27% of the mass and 76% of the REE minerals being recovered into 22% of the mass, respectively. In the case of magnetic methods, it was possible to reject 73% of the waste material at a crush size of -0.5mm, while it was possible to reject 78% of the waste material at a crush size of -2mm using gravity methods. Additional metallurgical tests are being conducted to optimize these processes even further.

It must be noted that these Exploration Target estimates are based on assumptions made from sparse geological data. The estimates cannot be construed as resources or reserves in any way, shape or form.

WRE built conceptual volumetric models covering the Overton Mountain and Red Mountain claim areas. The volumetric models were developed to estimate the volume of material within the claim areas and evaluate surface sample grades exceeding TREO of 2,500 ppm. The upper surface of the models is topography. The lower surface of the models is set to an elevation of 1,720 meters, which is approximately 30 meters below the average elevation of 1,750 meters msl at the base of Overton Mountain and Red Mountain. The mineralisation is similar to the depths observed at the La Paz REE project in Arizona, approximately 30 meters.

An Exploration Target with a range of approximately 307.8 – 384.7 million tonnes as estimated using the parameters listed above. The average estimated TREO grade ranges from 2,330 – 2,912ppm. It should be noted that a general range of 20% was applied to the tonnage, grade values.

"Wyoming is home to several major mining operations. The Project area has excellent road and rail infrastructure and is historically known to host rare earths…We have an alternative pool of technical experts, whose expertise will be beneficial as we also progress our La Paz Rare Earths project in Arizona.”
Creagh O'Connor
Non-Executive Chair | American Rare Earths & Western Rare Earths