Tuvatu Alkaline Gold Project
Lion One Metals Limited is set to become the premier high-grade gold producer in the South Pacific island nation of Fiji at its 100% owned and fully permitted Tuvatu Alkaline Gold Project. Lion One is focused on cost effective and environmentally responsible construction, development, and advancement of Tuvatu towards production, coupled with exploration of its district-scale license areas covering the adjoining 7km wide Navilawa caldera.
Location & Status
Tuvatu is located (lat.17º43’S, long.177º35’E) 24 km NE of the town of Nadi on the island of Viti Levu in the Republic of Fiji. The project lies between elevations of 100 and 600 m in the eroded crater of the Navilawa caldera, overlooking the Sabeto River valley and town of Nadi on the western coast of Viti Levu.
The area surrounding Tuvatu gold deposit and resource area is covered by a 3.85 km² Special Mining Lease (SML 62), with the broader project area covered by 13,619 hectares of Special Prospecting Licenses (SML’s 1283, 1296, 1465 & 1512), covering the balance of the Navilawa caldera. Permanent mine site facilities at Tuvatu are accessible by a service road connected to the Queen’s Highway a total distance of 15 km from the Company’s head office and assay laboratory, located 1.5 km from Nadi’s International Airport.
Geology & Mineralization
Fiji lies on the boundary of the Indo-Australian and Pacific tectonic plates, a zone marked by seafloor spreading and transform faulting. The Fijian islands are at the midpoint of the opposing Tonga Kermadec and New Hebrides convergence zones. It is separated from these actual convergence zones by two extensional back arc basins, the North Fiji Basin to the west and the Lau Basin to the east and a series of transform faults including the Fiji Fracture Zone and the Matthew Hunter Ridge. Approximately five million years ago (Miocene/Pliocene Period) the area was the site of a number of major volcanoes, formed along a northeast – southwest trend.
Navilawa is one of several gold systems associated with alkaline rocks along the NE trending Viti Levu lineament, Fiji’s own 250 km long gold corridor. A number of other gold deposits have been discovered along this trend including Vatukoula and Raki Raki. The Vatukoula or Emperor Mine has produced over 7 million ounces of gold since 1937.
Mineralization in the Navilawa caldera is driven by the emplacement of alkaline intrusive stocks (Navilawa monzonite), with subsequent stages driven by sector collapse and lateral spread into permeable units at the contacts of the monzonite intrusive.
Gold mineralization is dominantly hosted in the monzonite but also occurs in the adjacent volcanics. Mineralization is structurally controlled occurring as sets and networks of narrow veins and cracks, with individual veins ranging from 0.04 m to 9.0 m true width with a mean of 1.1 m. Lode mineralogy is varied, with most veins containing quartz, pyrite and base metal sulphides. A high proportion of the gold in the deposit occurs as either free gold or is contained in quartz or pyrite grains that can be extracted by simple floatation followed by cyanidation or direct leaching. Free gold is both fine and coarse grained although sample assay repeatability is very good suggesting most is fine grained.
The main mineralized zone at Tuvatu (Upper Ridges) comprises eleven principal lodes with a strike length over 600m and a vertical extent of more than 300m. Another major zone of mineralization (Murau) strikes east-west and consists of two major lodes with a mapped strike length in excess of 400 m. A total of 39 different lode structures have been identified in the Tuvatu resource area including 11 lodes in the Upper Ridges area, 3 lodes in the Murau area, 4 lodes in the West area, 2 lodes in the Tuvatu area and shallow dipping veins in the SKL area. Numerous additional lodes have been identified but require further testing to merit inclusion in resource estimates.
The Tuvatu mineral resource has been estimated for each vein individually using ordinary kriging of width and grade, the latter using accumulations, into a 3D block model. The Tuvatu resource is reported at a 3 g/t Au cutoff representing a resource amenable to underground production. The June 2014 Tuvatu resource estimate reported an indicated resource of 1,101,000 tonnes at 8.46 g/t Au for 299,500 ounces of gold and an inferred resource of 1,506,000 tonnes at 9.70 g/t Au for 468,000 ounces of gold.