Predictive Modelling Success Stories
- NZ Gold prospectivity mapping
- Ephitermal Gold prospectivity model for Aurora Minerals
- Mesothermal and Epithermal gold prospectivity models for HPD
- LINZ Mineral Valuation
- Cu-Au porphyry model for Solomon Gold Plc
- Epithermal and Carlin style prospectivity models for the Drummond Basin
- Iron Oxide Copper Gold in Namibia for Mandorin Goldfields Inc.
- NZ modelling to predict the best areas for plantation growth of specific varieties
- 3D modelling projects for HPD, L&M and Auzex
PMapNorth and PMapSouth were joint projects between GNS Science and Crown Minerals in New Zealand. The projects goal was to increase mineral exploration in New Zealand using prospectivity modelling to market the potential of New Zealand for gold mineralisation to the international exploration industry. As shown in the maps below permit coverage throughout New Zealand increased after the release of the PMap modelling results.
Area of land covered by mineral permits for prospecting, exploration or mining in New Zealand over four years from 2002.
The prospectivity study for gold in New Zealand is split into two data sets: PMapNorth for epithermal gold deposits throughout the North Island and PMapSouth for mesothermal gold deposits in the South Island. Both studies, including the base data, are freely available from Crown Minerals and can be viewed on our Web Maps in relation to current permit outlines: EPITHERMAL GOLD PMAP or MESOTHERMAL GOLD PMAP
Greg Partington introduced the concept of prospectivity modelling to GNS and Crown Minerals and managed both projects to completion. The PMap projects confirmed the value of prospectivity modelling to many in mineral exploration. The success of the PMap projects also highlighted prospectivity modelling as a marketing tool, which allows you to simplify complex geological concepts that can be understood by non geologists. [top]
HPD, who was acquired by Glass Earth (New Zealand) Limited, used prospectivity modelling to acquire and manage exploration on projects throughout Otago, Marlborough, and in the North Island of New Zealand. They used the prospectivity modelling to identify areas that lacked specific geological and geochemical data that could enhance the prospectivity of their targets.
This allowed HPD to design cost effective exploration programs, prioritise their project expenditure and rapidly identify those prospects that had the best chance of being developed. The tenement package acquired by HPD was considered highly prospective by other exploration companies who then offered HPD a variety of investment and joint venture proposals.
HPD NZ recently merged with Glass Earth, a new NZ exploration company, in a deal worth $4M to HPD NZ share holders. Glass Earth acquired the prospects developed through the modelling work done by Kenex. This valuable exploration land assembled by HPD land is today undergoing drilling and aggressive exploration by Glass Earth. [top]
It was recognised that the ongoing review of about 300 Crown Pastoral Leases in New Zealand by LINZ could result in their ownership being retained by the Crown primarily for conservation purposes, or sale to the leaseholders for continued productive use without consideration for the potential mineral value present on the land. Kenex were employed to develop a model of potential mineral values according to their probability of occurrence derived from prospectivity modelling carried out by Kenex in the South Island of New Zealand.
The study was limited to hard rock gold, coal, hard rock nickel (Ni), copper (Cu) and platinum group element (PGE) deposits of a particular geological association and one type of tungsten (W) deposit. Total values of the resources within the South Island for the four mineral categories were calculated from the results of a 1999 investigation into the mineral potential of New Zealand. LINZ provided outlines of the leases under review in digital form, and these boundaries confined the area for which the mineral values were determined. Values for each mineral category were derived from the proportion of prospective ground calculated from prospectivity models for each mineral type.
The prospectivity models for the metallic minerals were derived from private exploration company studies and as such do not cover all of the prospective land under consideration. More regional scale prospectivity models are required to properly assess the mineral potential of the area in question. A map was the developed of the mineral values for each mineral category on every lease area, highlighting the leases that contain significant mineral values.
The mineral value map developed for LINZ shows that, especially in Otago, there are more than NZ$50 billion worth of mineral resources within the area subject to the current HTCR review process. Much of this value is made up of two coal fields, which although small in area, are significant resources and given the debate in New Zealand on future security of power supply of great strategic importance to the country.
The project also shows how new spatial modelling techniques can be applied to land management, to answer questions such as where do the mineral values lie, what minerals, what is the opportunity cost of not developing minerals, how to make most efficient use of resources and how the country can utilise its resources best? [top]
Aurora Minerals floated on the ASX on four projects in New Zealand. Aurora recognised the value of the prospectivity modelling work carried out in New Zealand for gold. Kenex were employed to interpret the results of the prospectivity modelling, which led to the acquisition of the Hazelbrook and Lanigans projects in Northland for epithermal gold mineralisation, the Rockville project in the Nelson region and Macraes West in Otago for mesothermal gold.
The tenements were acquired 100% for the company at a low cost. The acquisition of the Northland permits was a bold move as there had been little exploration for gold in Northland to that time. Aurora discovered two new epithermal gold systems within six months of starting exploration in areas highlighted by the prospectivity modelling. Gold grades up to 7 g/t gold were recovered from rock-chip samples from surface quartz veins within the Backyard prospect.
The first drilling program completed at Backyard confirmed a significant epithermal system with large quantities of quartz and pyrite. The surface grades have yet to be replicated at depth. In addition the company identified several Eastern anomalies within the Huia trend, with a highest rock chip sample of 3.15 g/t gold. A gold in soil anomaly was also identified at the Toolshed prospect.
This initial success led to the formation of the Hazelbrook Joint Venture, which was formed between Aurora Minerals and Emerald Mining, with Emerald Mining to provide $10 million to earn 50, valuing the project at $20 million. The prospectivity modelling gave Aurora an immediate focus for exploration with early success allowing them to add significant value to their assets soon after start-up. [top]
Solomon Gold have been exploring in the Solomon Islands for nearly 15 years and because of rugged terrain and land access issues needed a more efficient way of targeting their exploration. They had compiled a significant historical database of exploration results, but mostly in hard copy form that limited its usefulness. Kenex helped Solomon Gold compile their historic data into digital form and then developed a prospectivity model for Cu-Au porphyry mineralisation on Guadalcanal.
The model confirmed the prospectivity of the area and helped Solomon Gold raise funds on AIM in the UK for further exploration. Since its February 2006 flotation the Company has extended its exploration work and finalised drilling sites at Mbetilonga, discovered a new porphyry system at Sutakiki and identified a new porphyry target at Mbetsihata. All these areas were highlighted as prospective by the modelling.
Gold assays at Sutakiki confirm widespread high grade gold in quartz veins up to 39 g/t gold with spot assays up to 1020 g/t gold, 3.3per cent. copper and 228 g/t silver. Average grades, in the veins sampled, are 7.34 g/t gold and 0.41 per cent copper. Drilling at Mbetilonga encountered mineralised and altered porphyry.
The prospectivity modelling helped Solomon gold market their exploration ideas to investors and more importantly reduced the amount of rugged terrane to be searched and land access negotiations required so saving so saving shareholder capital. The early success has provided an added bonus and added considerable value to the company to the delight of their share holders. [top]
Highlights of older projects:
Development of Epithermal and Carlin style prospectivity models for the Drummond Basin. Mandorin Goldfields Inc., an Australian based company, used the models for project acquisition and company growth.
Developed a national model in NZ to predict the best areas for plantation growth of specific varieties. The models were used in conjunction with modelled land values to identify economical land with high growth potential.
Completion of 3D modelling projects for Macetown (mesothermal gold – Otago, HPD NZ), Muirs (epithermal gold – Bay of Plenty, HPD NZ), Maratoto (epithermal gold – Waikato, HPD NZ), Ohai (coal - Southland, L&M Mining), Kingsgate (Mo, Bi - NSW, Auzex Resources).