Gold and tin were discovered in the Mt Todd area in 1889 and most early production from the area occurred in the period 1902 to 1914. The Jones Brothers reef is reported to have produced 28.45 kg of gold. In the latter part of this period exploration turned to tungsten with the discovery of the Yinberrie Wolfram field in 1913. In the 1950s regional exploration focused on uranium. In the 1970s exploration in the region once again focused on gold. In the 1980s drilling was conducted on the Quigley’s reef which resulted in modest historic production and more importantly the formation of the Billiton-Zapopan JV. The Mt Todd mineralization, or more specifically, the Batman deposit was discovered in May, 1988.
Commercial production from the Batman deposit commenced in 1993 with a heap leach operation processing 4 million tonnes per year (MTPY). This was expanded to 6 MTPY in 1994. Pegasus Gold became the owner/operator of the site in 1993 and in 1995 approved the capital expenditure to construct an 8 MTPY flotation and carbon-in-leach plant to improve recovery from that experienced in the heap leach operation. Commissioning of the new plant commenced in November, 1996. The flotation circuit was shut down in mid-1997 and on November 14, 1997 Pegasus put the entire Mt Todd operation on care and maintenance primarily due to low gold prices (below US$300 per ounce), low plant throughput, high reagent consumption and poor gold production. Mt Todd was operated briefly in 1999-2000 by a joint venture comprised of Multiplex Resources and General Gold Resources. Operations ceased in July 2000 and most of the equipment was sold in June 2001 and removed from the site.
Following the liquidation of the equipment on site, the Northern Territory Government (NTG) used what little bond money was available to make limited site modifications and became the operator of the Mt Todd site. Vista Gold acquired Mt Todd in 2006 through a series of contracts with Pegasus Gold Australia, the Jawoyn Aboriginal Association Corporation (JAAC), the NTG and the deed administrators. The JAAC are the freehold owners of the surface land in the area of the Mt Todd project. The NTG has retained the environmental liability for the Mt Todd site until such time as Vista has received all permits required to construct a new mine and makes a definitive investment decision.
Since acquiring the Mt Todd project, Vista has invested over US$100 million to advance the Mt Todd project. A significant investment has been made in areas related to Vista’s environmental stewardship for the site. Over 50,000 meters of core have been drilled to triple the gold resource of the project (now over 10 million ounces). Extensive metallurgical testing has been completed to evaluate the best technology to incorporate in the crushing and grinding circuits. Additional testing has been completed to assess the hardness and variability of the deposit and to give Vista the confidence that it has appropriately addressed all of the operational issues that challenged previous operators. Vista has completed several technical studies and in September 2019 announced the results of an updated preliminary feasibility, with an effective date of September 20, 2019, an issue date of October 7, 2019, and as amended September 22, 2020. This update incorporated the results of recently completed automated sorting and metallurgical tests which have contributed to lower capital/operating costs and improved gold production. The economic results of the study were reported at a US$1350 gold price and a US$0.70 per AUD exchange rate.