Rainbow Rare Earths Ltd, a rare earth element mining company, announced an update on its Gakara Rare Earth Project (‘Gakara’) in Burundi, where first production and sales of rare earth concentrate are on schedule for Q4 2017. Gakara is one of the highest grade rare earth element mining projects globally, with an estimated in situ grade of 47-67% Total Rare Earth Oxide (‘TREO’), and the Company is targeting a production rate of 5,000 tons per year (tpy) by the end of 2018.
• Completion of airborne magnetic survey suggests at least four large and highly prospective anomalies for a carbonatite source for Gakara’s rare earth veins providing
significant exploration upside potential,
• The anomalies range in diameter from 300 m to 2,700 m and have modeled starting depths of 20 m to 67 m,
• Consistent with Rainbow’s long-term strategy these anomalies present the targets for the Company’s first ever drill program when cash flows from operations allow
• Rainbow is on schedule to make first shipment of rare earth concentrate before the end of 2017 through distribution and off-take agreement with multinational Thyssenkrupp Raw Materials.
The Gakara deposit is made of a system of high grade veins, described as “stockworks”, with the veins typically varying in thickness from a few centimeters to up to 50 centimeters . Field observations have also shown that these veins pinch and swell, laterally and vertically, and that they can be continuous over tens of meters. Most scientific studies postulate that the Gakara rare earth mineralisation is associated with late-stage hydrothermal fluid phases expelled from carbonatite magmas into the earth’s crust and therefore, the genetic parent rock of the veins could be a large carbonatite intrusion in the form of pipe or several pipes, similar to kimberlite pipes that typically host diamonds.
Rainbow commissioned a helicopter-borne magnetic and radiometric survey, which was flown by New Resolution Airborne Geophysics (Pty) Ltd in the first half of October 2017 over the entire Gakara exploration licence, which covers approximately 135 km². The flight lines were East–West oriented with 50 m spacing between the lines and covered a total of 2,969 line-km. A survey altitude of 20-30 m above topography was employed. From the initial interpretation of the magnetic data, four conspicuous magnetic anomalies have been selected to date, although this figure may increase as the data is analysed further. These targets, which are indicative of large intrusions at depth, appear to be structurally controlled and vary in size from 300 m to 2,700 m in diameter. The depth estimates to the top of the bodies vary from 20 m to 67 m.
Each of the anomalies is close to major geological structures and is also either proximate to, or encompasses some of Rainbow’s existing rare earth prospects where high grade veins have been discovered. These targets further complement a ground based gravity survey at the Company’s Kiyenzi prospect completed earlier this year. Kiyenzi was selected for investigation due to the presence of large boulders at surface containing very high grade rare earth material. Results of this gravity survey suggest the presence of a further anomaly, which has been modeled as a sill-like oval structure potentially 22 m thick and 80 m x100 m in size.
Rainbow’s exploration strategy has focused to date on extending the Company’s understanding of the deposit, both in advancing near term new mining areas to augment
initial operations at Gasagwe and to seek the possible carbonatite source or sources for Gakara’s extensive vein stockworks. The results from the recent airborne survey and the Kiyenzi gravity survey supply Rainbow with ready made, large and highly prospective targets warranting further investigation through a drilling campaign when cashflows from operations allow. In addition, the airborne survey has provided Rainbow with a detailed geological and structural map of the entire exploration licence, showing previously unmapped lithological domains and better delineating reported geological formations; and also comprehensive data to assist decision making around the scheduled expiration of the Company’s Exploration Licence area in 2018.