An area centred ~20 km south-southwest of Kimba is being explored for possible buried Tanami style orogenic lode gold and also for Mount Isa / Broken Hill style base metals mineralisation, which could occur within reactive chemical and pelitic...
An area centred ~20 km south-southwest of Kimba is being explored for possible buried Tanami style orogenic lode gold and also for Mount Isa / Broken Hill style base metals mineralisation, which could occur within reactive chemical and pelitic metasediments and iron formation of the Hutchison Group, and be spatially associated with intercalated late syn-tectonic granitoids. During the first licence year, Monax Mining (Monax) acquired a detailed ground gravity survey and undertook a reconnaissance field trip during which 5 rock samples were collected for assaying and petrological examination. A number of fault structures were targeted to look for signs of alteration or mineralisation in the adjacent bedrock. The helicopter-assisted gravity survey comprised 1017 stations read in March 2006 over a regular 1 km x 1 km grid, and the resulting data revealed a series of north-south trending, relatively linear gravity highs which generally coincide with regional magnetic trends, and were thought to be lithologically controlled by BIF strata of the Hutchison Group, with bed fracturing caused by subsequent Kimban Orogeny deformation evident across strike. Monax undertook rock ship sampling of gossanous outcrop from the historic Argent silver prospect, where 5 samples were collected over an area of ~100 square metres, and returned high assay values of zinc in all samples (between 995 to 1187 ppm Zn) plus elevated gold in four samples (between 35 to 54 ppb Au). The petrologist reported that the host rocks are weathered gneisses, having quartz, limonite, goethite and supergene carbonate (in sample ARG3), and minor to abundant very coarse crystalline graphite. During licence Year 2, Monax conducted reconnaissance soil and rock chip geochemical sampling over the Argent and Standley mine prospects. 9 rock chip and 38 hand augered soil samples were collected, the latter to provide an orientation survey for determining the applicability of conventional soil sampling and/or partial leach soil sampling as an exploration technique to characterise the chemistry of shallowly covered bedrock. Follow up detailed soil sampling of zinc anomalism was planned for these prospects, comprising up to 500 samples along 2-3 km of strike length. If the soil sampling proved effective, excavation of costeans and RC drilling might be done to examine the petrology and mineralisation of the unweathered sediments at depth (conceivably Katunga Dolomite). Other work comprised continued detailed interpretation and modelling of magnetic and gravity targets, and the planning of a detailed, 100 m line spaced airborne magnetic and radiometric survey. During licence Year 3, in June-July 2007, Monax did not conduct soil and rock chip geochemical sampling for zinc as had been planned. Instead, a consultant geophysicist was engaged to undertake modelling and detailed interpretation of the magnetic and gravity data, and to identify mineral exploration targets. The orientation soil sampling results were received and appeared successful. The abandoned historic Argent mine lies within the Lower Middleback Jaspilite, and soil samples from above the line of lode showed encouraging enrichment in Au, As, Ce, Co, Cu, Nd, Ni, Pb, Sn, and Zn. The anomalous geochemistry decreases to near background levels towards the east, passing into the mapped Warrow Quartzite. In January 2008, extensive rock chip sampling (55 samples) was undertaken to determine the potential for iron ore grade mineralisation associated with the magnetic BIF units striking north-south throughout the tenement. Values of up to 60% Fe were returned. Two separate rock chip sampling sorties, for following up historically identified manganese potential within weathered Hutchison Group schists and gneisses, were conducted during April and May 2008 at WMC's Jamieson Tank, Pollinga and Hodgins prospects (20 samples assayed, returning up to 54.1% Mn). After Marmota Energy farmed into EL 3357 and began working towards earning 70% of the uranium rights by managing a separate new exploration programme that was searching for for basement, unconformity-related and palaeochannel hosted roll-front style uranium mineralisation, it acquired a detailed, 12,341 line km fixed wing airborne magnetic and radiometric survey in May 2008, and also a 3160.5 line km airborne 25 Hz TEMPEST EM survey shortly afterwards. Flight lines for both surveys, covering the whole of EL 3357, were orientated east-west at 100 m and 400 m spacing respectively; nominal sensor heights above the ground surface were 50 m and 120 m respectively. The new aeromagnetic data were said to have greatly improved the resolution of the main magnetic features seen within the tenement. Strong north-south trending magnetic highs due to BIF are prominent. The central area shows evidence of complex fold interference patterns. Strong east–west compression resulted in tight to near isoclinal north-south trending upright folding, which have been syn- to post tectonically overprinted by a northwest-southeast shearing. Those northwest-southeast structures heavily influence the structural trends, and offset the lithological units. During licence Year 4, in May-June 2008, as part of a shift in exploration focus away from the original aims towards assessing BIF-hosted ferrous metals prospectivity like that known to occur in related rocks in the Middleback Range, Monax did first pass RC drilling (48 inclined holes for 2956 m) to test the width, depth, and strike extent of identified manganese mineralisation subcropping at the Jamieson Tank, Pollinga and Lambell prospects. This campaign was followed by laboratory bench scale sighter mineral beneficiation testing to determine what are achievable grades and yields of manganese from selected drill intersections. The holes encountered significant manganese and iron mineralised intercepts, and 883 downhole cuttings samples were assayed. Relatively low levels of sulphur and phosphorus were reported within the manganiferous zones, which is favourable metallurgically. As part of the beneficiation tests, 3 selected samples were first subjected to quantitative XRD analysis, which showed that the manganese mineralogy is mainly cryptomelane. Sample screening on its own did not yield a product with +52% Mn oxide (= >40% Mn) content, nor did the use of a spiral gravity separator, and putting it through subsequent Davis Tube Recovery magnetic separation made very little improvement. But performing heavy liquids separation at SG 3.32 yielded 54.8% Mn oxide from hole JTRC036, with 81% recovery, indicating that overall, upgrading of the manganese to economic concentrations may be possible. So the company began seeking a joint venture partner to fund continued exploration for manganese mineralisation in the Jamieson Tank and Pollinga areas. Marmota began a process of ground truthing the detailed airborne radiometric survey and EM survey data, but did not do any field work. During licence Year 5, Monax entered into a farm-in agreement with OM (Manganese) Limited which was defined only for the exploration of ferrous metals - rich minerals within EL 3357. Under the terms of this agreement, OMM could earn a 60% interest in the ferrous minerals (iron and manganese) by spending $2,000,000 on exploration within 4 years. It was stipulated that OMM must spend a minimum of $250,000 in the first year before they might exercise the right to withdraw. Under the new farm-in agreement, orientation rock chip and soil geochemical sampling were performed in October 2009. Samples were collected at 25 m intervals along traverses paralleling the existing Monax RC drill traverses. Subsequently, in January-February 2010, 1:5,000 scale geological mapping, rock chip sampling and ground magnetic survey readings along lines 25 m apart were done at the Jamieson Tank prospect. In total, 64 rock chip samples were taken and assayed for a standard manganese suite, and more than 120 line km of ground magnetic data were acquired. In February 2010, Monax conducted extensive auger soil sampling at Jamieson Tank, when 685 samples were taken at 10 m intervals along 16 traverses. In May-June 2010, an RC/RAB drilling campaign of 83 inclined holes for 4565 m tested the strike extent of manganese mineralisation from north of Cultivator Hill southwards as far as the tenement boundary. Drillhole samples were submitted to be assayed for the standard manganese suite. Marmota undertook a detailed review of uranium potential on the tenement, and concluded that exploring for unconformity style targets should provide the best chance of future success, since many of the factors viewed as critical to emplacement of such mineralisation appeared to exist at Waddikee. A strategy for locating possible trap sites was devised where reductant host rocks, migration pathways for dissolved uranium and suitable near surface precipitation environments intersect. Four such inferred sites were chosen in the western part of the tenement, close to where recent Monax rock chip sampling had returned elevated uranium contents. In November 2009, Marmota performed a reconnaissance ground radiometric survey on EL 3357 which was intended to obtain representative background uranium, thorium and potassium radiation spectral values for the different outcropping basement stratigraphic units and for typical soil covered areas, to use as an aid in the interpretation of its airborne radiometric survey data. 112 measurements were made in situ using a SAIC Exploranium GR-135 Plus spectrometer. The salient observations were as follows: • outcropping felsic rocks such as granitic gneiss, pegmatites and Carappee Granite have the strongest radiometric response, relative to other outcropping units and the soils tested, which confirmed the airborne radiometric interpretation. • graphitic schist has the highest uranium response, and may be a good target for uranium mineralisation. • surficial lake sediments gave high uranium and thorium spectral readings, as was shown by the airborne radiometric survey. To assist with its envisaged uranium exploration going forward, Marmota made application to PIRSA for the grant of PACE Initiative Year 6 collaborative drilling subsidy funds that would allow it to test its theory that uranium had precipitated from oxidised U-bearing groundwaters within the base of palaeochannel systems where the substrate to the channel comprises reducing graphitic horizons within the Hutchison Group. This theory was put forward as a hybrid between the accepted palaeochannel and unconformity styles of genesis of secondary uranium mineralisation.