Exploration and Mining History
Desert Lion Energy is a lithium development company and early-stage producer focused on building Namibia’s first large-scale lithium mine. The company holds an 80% interest in the project, within its exclusive prospecting license (EPL), which covers 301km2 (EPL 5439) and consists of three past producing mines.
The pegmatites of the region (including Desert Lion Energy’s Rubicon and Helikon mines) have been the subject of a number of geological surveys and research investigations since the early 1930s. Since then, the Rubicon and Helikon deposits were developed, which included work on the open pit and underground workings.
At Rubicon, the main pegmatite was selectively mined from a series of pits and underground workings primarily for its petalite, amblygonite, lepidolite, beryl, quartz and accessory pollucite and bismuth. Mining commenced in the 1950s, however no information on production prior to 1980 is available. Between 1980 and 1994, production from the Rubicon and Helikon mines were focused on production of beryl, tantalum, amblygonite, petalite and lepidolite with target head grades of between 1.7% and 3.8% Li2O recorded. Material that was either not required or did not meet the exceptionally high in situ grades was stockpiled and collected next to the mining operations.
Geology and Mineralization
The Desert Lion Energy lithium project is located in the southern central zone of the Damara Belt in which many world class economic deposits have been discovered. Included amongst these deposits are lithium-beryllium (Li-Be), tin (Sn) and tourmaline-bearing lithium caesium tantalite (LCT) type family pegmatites and uranium (U) bearing niobium yttrium flourine family pegmatitic leucogranites, which intruded into the tightly folded supracrustal rocks of the Damara Supergroup.
The pegmatites of the Damara Orogen occur within five major belts with those in the Southern Tin and Karibib Pegmatite belts containing large, well zoned Li-Be gem tourmaline bearing LCT type. The Karibib Pegmatite Belt contains numerous LCT occurrences and workings, with the Rubicon and Helikon pegmatites being classic examples of highly fractionated and well zoned LCT pegmatites.
At Rubicon, a series of stacked sub parallel pegmatites intrude a variable dioritic and pegmatitic granite sequence with the main Rubicon pegmatite body forming a prominent ridge, which strikes approximately 900 metres (m) northwest and dips between 20º and 65º to the northeast; with dips averaging 45° near surface, flattening to about 18-25° at depth.
The main Rubicon pegmatite consists of two ellipsoidal well zoned, Li-mineralized bodies developed around two quartz cores and surrounded by a zone of quartz-feldspathic pegmatite. At Rubicon, the main lithium minerals present are lithium micas (comprising lepidolite and petalite). Historical mining has also produced waste dumps and slime dumps that contain lithium mineralization predominantly hosted in lepidolite, with minor petalite and tantalite.
The historical Helikon occurrences comprises a series of stacked, sub parallel LCT type pegmatites that were intruded into marbles and calc silicates belonging to the Karibib Formation. All five of the pegmatite exposures have in the past been exploited for lithium bearing minerals (lepidolite, petalite and amblygonite), tantalite as well as beryl. Helikon 1, located 750m south of the Helikon 2 to 5 targets, is the largest exposed pegmatite at the project with a strike length of 350m, an average thickness of 65m and dips 70° to the north. The Helikon 2 to 5 pegmatite targets define a discontinuous strike length of approximately 1,700m with variable dips and thicknesses.
Maps and Drill Results
Desert Lion Energy began production of lithium concentrate from stockpiled material in December 2017. Prior to production, there was approximately 700 thousand tonnes (kt) of stockpiled material and 100kt of fines located on Desert Lion Energy’s exclusive prospect license, scheduled to be processed in Phase 1 of the company’s production plan, which spans a 12- to 18-month period.
Following the production of lithium concentrate from stockpiled material (i.e. Phase I production), Desert Lion Energy plans to commence production of lithium concentrate from in situ ore (i.e. Phase II production), which is expected to begin at the end of 2019. The Phase II production schedule will be based on results of a Preliminary Economic Assessment, which the Company plans to publish in 2018.