Gold Mountain’s recent trial soil sampling at its Casa Nova project in Brazil has revealed a zone it believes is anomalous in several critical elements including lithium, caesium, beryllium, tin and gallium.
The company says it may represent components of a classic pegmatite-hosted lithium, caesium, tantalum (LCT) mineralised system. The trial was conducted within only a small part of its 495-square-kilometre project.
Management says the project’s copper-nickel potential became evident after its ears had pricked up on announcements made by the Bahia Geological Survey that the dominant mafic-ultramafic rock assemblage of the Caboclos dos Mangueiros nickel-copper deposit, 230km west of Casa Nova, may correlate with those in the company’s project area.
It now believes its soil data from the trial grid may suggest that the extent of mafic intrusives could be more widespread than currently mapped.
Gold Mountain’s trial program was comprised of four lines set 400m apart, with samples taken 25m apart to confirm the method’s effectiveness in identifying base metals signatures in areas of thin, wind-blown sand cover. The work was also designed to confirm the previously-reported presence of lithium-bearing pegmatites in the area, in association with mapped mafic and ultramafic intrusive rocks.
The company’s first move was to check the area of previous work and it identified several granite outcrops near abundant pegmatites. Visual inspection was unable to identify spodumene in the pegmatites, but that is not unusual on a hand specimen scale.
Management says the program proved successful despite the thin sand cover and confirmed not only a measure of base metal anomalism with elevated nickel, copper, iron and vanadium signatures, but also a zone with elevated lithium, caesium, beryllium, tin and gallium responses. It believes the zone, which contains many pegmatites, might be the source of lithium-bearing fluids.
Values in its soil anomalies were up to a maximum of 49 parts per million lithium oxide, with a background interpreted at 16ppm lithium oxide. From a total of 14 rock samples, three yielded respective results of 90ppm, 201ppm and 300ppm lithium oxide, all falling within the LCT element zone defined by the soil sampling program.
Gold Mountain says it is encouraged by the Bahia Geological Survey’s lithological descriptions of the typical suite of intrusives within its project area.
The company may design future work to test whether Casa Nova is common to many other mafic-ultramafic-hosted, chonolith-style nickel-copper deposits, including the Nebo Babel, Savannah and Nova Bollinger deposits.
As a result of its trial outcomes, Gold Mountain is now likely to consider shallow soil sampling beneath sand cover to test the continued effectiveness of the method in identifying or confirming both base metal and LCT anomalism across key areas of interest. It may also pursue stream sediment sampling where suitable drainage exists, in concert with other supportive reconnaissance methods such as mapping, high-resolution aeromagnetics or induced-polarisation (IP).
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By Doug Bright
