Mr. Barrie Bolton - Honours Projects
Characterisation and Genesis of Manganese Deposits at Wandanya, East Pilbara, WA
Supervisor: Barry Bolton & Andrew Frierdich
Fields of Study: Economic geology
Support Offered: All travel, field, analytical & thesis-preparation costs
Perth-based exploration company, Black Canyon Limited (ASX: BCA), has recently announced the discovery of a high-grade stratabound manganese deposit on the eastern margin of the Oakover Basin in the East Pilbara region of Western Australia (see their website at www.blackcanyon.com.au for further details).
While manganese mineralisation is widespread in the Mesoproterozoic Oakover Basin this discovery appears to represent a shallow dipping stratabound manganese horizon of consistently high grade (up to 8m @ 31.1% Mn) over hundreds of metres of strike and at
shallow depth (<10m from surface). Preliminary drilling at the prospect also shows manganese is interbedded and typically down-dip from thick (up to 12m), stratabound deposits of high-grade iron mineralisation (up to 64.2% Fe). The mineralisation is dominated
by iron oxides (hematite and lesser goethite/limonite), manganese oxides (unknown but likely cryptomelane, psilomelane and pyrolusite) and manganese carbonate (likely rhodochrosite). The primary manganese carbonate has been upgraded through weathering to form the secondary high grade manganese oxides.
Both manganese and iron mineralisation appear to be fault related and precipitated from hydrothermal solutions in a gently folded, sedimentary sequence comprising, from the base, a footwall dolomite, a spotted manganese dolomite, massive manganese and manganese dolomite breccia overlain by hanging wall dolomite.
Supergene processes are also thought to have played a significant role in the evolution of the high-grade Mn and Fe mineralisation present at Wandanya.
This field- and laboratory-based study will involve mapping of Mn and Fe occurrences as well as re-logging RC chips, logging drill core to determine their stratigraphic and structural setting and follow-up geochemical, mineralogical and petrographical analysis to characterise
the nature and origin of these potentially important deposits. The work will also aim to better understand the timing of mineralisation, fluid sources, mode of formation and the role of supergene processes in their formation. This study will also compare this style of
mineralization to the manganese mine at Woodie Woodie, just to the north of the Wandanya prospect, looking for similarities and differences based on published information.
For further details contact: Barry Bolton
On the Nature and Origin of Manganese Deposits at Heathcote, Victoria
Supervisor: Barry Bolton & Andrew Frierdich
Field of Study: economic geology
Support Offered: all travel, field, analytical & thesis-preparation costs
Manganese, the third most traded metal in the World after iron and aluminium, is primarily used in steel production but increasingly in batteries as part of the move to electric vehicles.
Victorian manganese deposits are restricted to a few small occurrences, predominantly of secondary origin and derived from volcanic rocks. These deposits are principally a mixture of manganese and iron oxides. The manganese minerals are the oxides pyrolusite (Mn02) and psilomelane, which may contain variable amounts of cobalt, copper, zinc, barium and 10 to 20 per cent water (known as wad when amorphous and earthy in appearance). The deposits result from the decomposition of other ores - oxides (including pyrolusite), sulphides and magnesian carbonates (dolomite).
The principal deposits in Victoria are at Heathcote (primarily Bald Hill), where approximately 420 tonnes of manganese ore was mined intermittently between 1910 and 1927. This deposit has been variously described as a “stockwork of small veins”, and “of considerable dimensions”. The grade of this deposit averaged 53% MnO2, with highest grade recorded of over 80% MnO2. The manganese ore appears to have been hosted by a series of contorted, iron-rich sediments, originally possibly banded iron formation type. Both
manganese and associated iron deposits are hosted by Cambrian aged sediments and volcanic rocks that comprise the Heathcote greenstone belt.
This field and laboratory-based study would include field mapping to better understand the geological setting of manganese deposits as well as follow-up laboratory studies to characterise the petrology, mineralogy, geochemistry of the deposits and to better constrain
our understanding of their mode of origin.
For further details contact: Barry Bolton