Less than four months after identifying a monster magnetotelluric (MT) anomaly at Ausmex’ (AMG.ASX) South Australian, Burra site, Professor Graham Heinson of the University of Adelaide finds high conductivity levels less than 5km below the Ausmex’ Burra grid.
“We find that there is a region of very high electrical conductivity at a depth of 1-5 km below Burra, this extends to the south towards Kapunda in a relatively narrow band. The electrically conductive structures appear to bridge to the surface near Burra. Although we don’t know exactly what causes the high conductivity, the presence of sulphide minerals that often are concentrated along the hinge lines of major folded structures is a major candidate,” stated Professor Heinson.
Sulphide minerals are the major source of precious metals across the globe, including, but not limited to gold, silver, platinum, cobalt copper and zinc. Consequently, this electric conductivity discovery comes as exciting news to researchers and miners alike.
By combining the efforts of Professor Heinson and a refined magetitelluric technique, Ausmex are successfully able to utilize the scientific findings to more accurately source ‘hot spots’ and drill those that are of mineable depth. Professor Heinson believes that in areas of old mineralisation, such as Burra, the likely conductive materials to be found are sulphides and graphite. This comes as exciting news, as the Burra mine has produced more than 2.7 million tones of copper ore for miners since the 1850’s.
Magnetotellurics (MT) is a geophysical technique that uses naturally occurring variations in the Earth’s magnetic and electrical fields to measure the electoral resistivity of the earths sub-surface. By identifying the electrical resistivity of the Burra site, surveyors such as Professor Heinson can better understand the deep geological structure of the earths sub surface, including the locations of world-class sulphide mineral deposits. “The size of the current depends on the Earth’s ability to conduct electricity, which in turn depends on the minerals, presence of water and in some places if there is molten rock,” explained Professor Heinson.
Despite the technique of MT being developed in the 1950’s, advancements in the capacity in which data can be collected, as well as innovations in the surveying instruments used throughout the 21st century, means current modelling methods can easily yield 3d images on the earths conductivity extending down tens of kilometres. This is proving to be a standout feature when comparing MT technology to other methods used within the market. The MT technique also omits no environmental impact, encouraging its use.
Overall, the current technological assessment of the large IOCG targets located at the Ausmex site is an optimistic one, equally from a scientific and economic standpoint, as the IOCG amounts that have been discovered are particularly rare to Australia.
To date, the survey has been carried out across 7,010 sq. Km of the Burra grid. A second lot of geophysics is to be conducted during February/March to help identify drilling targets and access IOCG mineralisation.