The Adelaide Hills Project consists of 3419 square km of land covered by eight contiguous exploration licences, ELs 3057, 3064, 3141, 3215, 3239, 3277, 3425 and 3534, which are owned by or joint ventured to Flinders Diamonds Limited (FDL). By an...
The Adelaide Hills Project consists of 3419 square km of land covered by eight contiguous exploration licences, ELs 3057, 3064, 3141, 3215, 3239, 3277, 3425 and 3534, which are owned by or joint ventured to Flinders Diamonds Limited (FDL). By an agreement dated 29/7/2005, Maximus Resources Limited (MXR) was assigned beneficial ownership of and has the sole right to explore for all metalliferous minerals within these tenements, except for on EL 3277 Kanmantoo. The subject tenements have been given combined exploration expenditure commitments and joint reporting status. During the fourth year of the project, MXR undertook gold exploration, focussing on the Bird-in-Hand mine area of the Woodside Goldfield located on EL 3215 Lobethal, where past South Australian Department of Mines' diamond drilling in 1933-1934, and other appraisal drilling done by Capricorn Resources NL in 1997, had intersected gold mineralisation below the old workings. Between November 2005 and April 2006, MXR drilled 8 vertical rotary mud - precollared and HQ diamond cored holes for a total penetration of 1734.2 m. Two main lodes were encountered in a fractured dolomitic limestone within a sequence of sandstones, limestone and siltstones. Each lode comprises gold-bearing quartz veins which generally vary from 0.5 to 5.0 m thick. The widest intercept made, some 13 m in true thickness, was in hole BH21; but MXR assumed from this that the previous miners had concentrated on mining an individual quartz vein (and had not investigated the wider zone of mineralisation reflected in this intercept), as this view of their working style can be inferred from the few historic cross-cuts which are evident in the 1930s underground mapping and sampling records. The widest and best mineralised intercept was obtained by MXR in hole BH17, of 9.04 m @ 31.2 g/t Au, 58.3 g/t Ag, 0.41% Cu, 5.8% Pb and 4.6% Zn, from the depth interval 158.5- 167.54 m. Narrow 0.5 m to ~1 m wide veins carrying much richer grades of up to 226 g/t Au and 303 g/t Ag were encountered in three other holes. Some significant, but localised at depth, base metal contents were returned in the drill core assay results. MXR announced that the latest drilling results had confirmed the extension of gold mineralisation below the old workings at the Bird-in-Hand mine to a depth of ~200 m below the surface, or 100 m below the recorded historic workings. An initial inferred resource of 116,000 t @ 14.2 g/t Au, containing 53,000 oz of gold, was provisionally estimated. At this gold grade, the deposit is amenable to underground mining provided that sufficient tonnes are proven to exist. Petrological work was carried out on selected mineralised samples to help to understand the mode of occurrence of the gold. The findings showed that the gold exists as free particles of between 3 and 150 microns in size, that are located within and along fractures throughout pyrite grains, and are also less commonly located within base metal sulphide grains. Leach testwork was undertaken on composite drill core samples of the high grade gold-in-quartz/sulphide mineralisation, and results indicated that the gold was amenable to cyanide extraction techniques, with high recoveries recorded on each sample. This preliminary work suggests that there is negligible refractory gold. A numerical analysis of 556 old mines in the Adelaide Hills was undertaken by consultant David Miller, who compiled data about their gold production, grade and geology. He identified 41 mines of interest to MXR's modern-day gold search, which are broadly located in five distinct geographical areas – Birdwood-Mount Pleasant, Deloraine, Palmer, Lobethal and Woodside. Following the intersection of massive base metal sulphide mineralisation in holes BH17 and BH20, attempts were made to case several of the open holes with 32mm PVC. This was achieved for holes BH20 and BH21, but subsequent probing of BH21 indicated that the casing had blocked just as it passed into the mineralised zone. On 31/10/2005, ground magnetic survey traverses were undertaken over the Main and Victoria shaft areas at Bird-in-Hand, but all of the magnetic responses seen from 14,607 closely spaced readings were interpreted as arising from subsurface relics of previous mining and ground water extraction activities. After the drilling programme was completed, a downhole IP survey was conducted by Search Exploration for MXR in collaboration with consultant geophysicist, Graham Boyd. In this survey, a downhole electrode was used to read current provided by four alternate surface electrode positions set out N, S, E and W around holes BH20 and BH21. Verbal discussion of the results with Mr Boyd indicated that the method was able to detect the massive sulphide intersections but, due to some difficulties in ascertaining electrode polarities at the time of the actual survey, a definitive interpretation of the results was not possible. However, MXR is intending to case all new drillholes on the understanding that the downhole IP technique can be further trialled, with a view to determining the direction in which further drilling should best be undertaken to try to locate other sulphide-enriched lode sections. During the fifth, 2006-2007 project year, MXR conducted a second campaign of appraisal drilling on the Bird-in-Hand gold prospect, commencing in September 2006. Another 8, now inclined RC - precollared and HQ/NQ diamond cored holes for 2366.6.m were completed, aiming to define a down dip extension of the gold mineralisation to 400 m depth, which is 300 m lower than the No. 5 level, the base of stoping from historic mining operations. This primary objective was attained. The first two holes of this campaign, BH24 and BH28, were partly subsidised by PIRSA as an approved collaborative drilling project through Year 3 of the PACE Initiative (see Env 11391 for the previously released final report on Project DPY3-49). RC drilling was the most successful technique used for the hole precollaring. However, this precollaring was only successful down to 60-100 m depth, before ground conditions became too difficult for this method to handle, necessitating having to convert to diamond drilling. Difficulties encountered included when very soft sandstone units within the Tarcowie Siltstone collapsed in on the drill string, ingress to the holes of excessive volumes of groundwater, and inadequate rig capabilities. Drilling in general was very difficult and slow, primarily due to the very fractured and broken nature of the ground being penetrated. Most holes started with an RC precollar before continuing with HQ and then NQ diamond drilling through the mineralised sections. Only holes BH29 and BH30 were completed in HQ. Problems experienced during the precollar drilling for hole BH28 resulted in the eventual hole trajectory lifting severely and therefore not reaching the targeted depth of 400 m below surface. Poor drill core recoveries of the mineralised section (approximately 40%) also occurred in this hole. MXR therefore elected to undertake a wedge (BH28W) off this hole from 288 m distance downhole, with the aim of obtaining better core recoveries through the mineralised section. Despite the core recoveries so obtained turning out to be very similar to those from the parent hole, it was later found that the grades of the mineralised section in the wedged-off hole portion are significantly better. The first-completed hole, BH24, was continued approximately 80 m into the footwall as proposed in the PACE Initiative grant application. The aim of doing this was to search for a back reef lode position that had been described by the miners in the 1890s. A small, ~2 m zone of quartz veining was intersected in this position but was barren of any mineralisation. As planned, a number of holes drilled in the 2006-2007 reporting period were cased with slotted PVC to enable downhole IP or EM surveying to be undertaken in the near future. Holes BH24, BH29 and BH30 were all cased to EOH, while BH26 and BH27 were cased to ~200 m downhole, at which points those holes became blocked. Soil geochemical sampling was undertaken on a small area of land (approx. 300 m x 600 m) immediately to the south of the Ridge mine, for investigating possible extensions of mineralisation towards the Nest Egg mine. Samples were collected at 50 m intervals along E-W lines 100 m apart, using a post hole digger to take soil from the “B” horizon at depths of between 30 cm and 60 cm. The assay results were generally poor, with only minor isolated anomalous values for various elements. A single gold value of 14 ppb Au was recorded at the end of one line near the old Ridge workings, and is interpreted as surface contamination from there. Consultant David Miller was retained to conduct a detailed analysis of all available past drainage sampling records from within the project area, to highlight any clusters of significant geochemical anomalism worthy of follow-up as possible indicators of nearby Bird-in-Hand type buried gold and/or base metal occurrences. He exposed a number of complex issues with data cleansing and management that required resolving prior to any digitisation and subsequent data manipulation and interrogation phases. During the sixth, 2007-2008 project year, MXR began to widen the gold search space within the project tenements, while still continuing to explore and evaluate the Bird-in-Hand gold prospect. Three additional ELs were applied for covering ground around Williamstown, Tepko, and Mount Monster in the ranges behind Willunga. Further drilling confirmed the extension of mineralisation below the old workings at the Bird-in-Hand mine, to now reach down to about 450 m below the surface, or 350 m below the old workings of the mine. It was apparent that the extent of mineralisation still remains open at depth. A revised estimate for the inferred gold resource at this prospect, of 420,000 t @ 12.0 g/t Au, containing 162,000 oz, was made in July 2007. A further upgrade to this resource will be generated, based on the recent drilling information. 13 inclined or vertical diamond drillholes for 3129.45 m were completed during the reporting period, to probe the deposit at depth and also to infill at shallower levels to better define and characterise the resource. A best mineralised intercept of 14.2 m @ 15.5 g/t Au was recorded from the cored depth interval 375 to 389.2 m in vertical hole BH42. In February 2008, wireline geophysical logging was done in this hole, using gamma, neutron, induction and resistivity tools. The geophysical data were collected mainly to assist the interpretation of groundwater quality results obtained from water samples collected from depth within the hole. Groundwater consultants Aquaterra were engaged by MXR to advise the company about a doing a suitable programme of groundwater research, monitoring and management that would inform a mining prefeasibility study. Geophysical anomalies generated by new ground magnetic and IP surveys that MXR acquired in the historic Cromer alluvial goldfield area on EL 3141, which is located ~3 km north of Birdwood, were explored by drilling 5 inclined RC holes plus 1 vertical RC hole, for a total of 882 m. Although >3000 oz of alluvial gold is recorded as having been found there, the bedrock sources for most of it are unknown. Each of the drillholes intersected a substantial zone of gritty red brown clay that overlies fresh micaceous schist. This muscovite-biotite schist shows signs of minor chloritic alteration and has quartz veining which contains small amounts of pyrite. No significant primary mineralisation was encountered, the best intercept being 4 m @ 0.2 g/t Au. The ground magnetic survey response seen here was attributed to fine grained disseminated magnetite that is concentrated within 1 m to 5 m wide bands. Four lines of dipole-dipole IP survey readings were also acquired here to try to define sulphide accumulations which might be the sources of the secondary mineralisation. During July 2007, a ground magnetic survey was acquired over a 1 km x 1 km area centred on the historic Bird-in-Hand mine site. The magnetometer traverses were mostly run E-W, with a nominal 20 m line spacing (except in heavily wooded areas). After some analysis of the magnetic data, an additional survey was undertaken in November 2007 over a small area immediately to the south of the main survey. Another ground magnetic survey was read in the Eureka Goldfield area, also located on EL 3215, coverage amounting to 500 square m. Because the known lode trends N-S, the magnetometer traverses here were also run E-W, the lines being 50 m apart. The aim was to define structures associated with the known mineralisation. In addition, two lines of IP readings were made across this prospect. A fourth ground magnetic survey was read across a 500 square m area at the Deloraine Goldfield located on EL 3534, also along E-W lines spaced 50 m apart. Petrological work was carried out on selected mineralised rock samples taken from the Eureka and Deloraine prospects, to gain an understanding of the bedrock lithologies associated with the deposits and the alteration associated with the mineralisation. Reconnaissance soil geochemical sampling was conducted across several old gold prospects, seeking to reveal pointers to possible extensions of mineralisation. The sampling density was 50 m x 50 m. Areas to the east of the Ridge mine, around the Eureka workings to the north and south, and between historic workings at Cromer were thus sampled. The assay results were unremarkable, with isolated elevated gold values coming from sample sites lying close to the former workings, and so likely to represent surface contamination. 39 grab rock chip samples of bedrock outcrops were collected around the Bird-in-Hand prospect, with variable results. A number of samples taken from the Ridge deposit old workings returned up to 9.5 ppm Au. Another sample taken from the road cutting between the Bird-in-Hand and Ridge deposits returned a value of 16.2 ppm Au. During the seventh, 2008-2009 project year, in August 2008, MXR announced an updated, combined inferred and indicated resource for the Bird-in Hand gold deposit of 598,000 t @ 12.3 g/t Au, containing 237,000 oz of gold. A further 5 vertical or inclined diamond drillholes for 1359.8 m were completed in the reporting period to better define the lateral depth and extent of the lodes and wall rock mineralisation at Bird-in-Hand, and to test for blind shoots along strike. 2 of these holes (RDH1 and RDH2) were drilled ~ 250 m to the south-west of the mine to test the continuity at depth of known mineralisation at the Ridge workings. In June 2008, another drillhole, BH43, was wireline geophysically logged using gamma ray, induction and magnetic susceptibility measuring tools. A small amount of soil geochemical sampling was done in the south of the Woodside Goldfield on EL 3215 to try to link known mineralisation at historic workings there. An extension ground magnetic survey was acquired at the Deloraine prospect on EL 3534, covering the line of lode to the south of the old workings. In October 2008, after their analysis of a number of groundwater samples and the interpretation of MXR's exploration drillhole logs and downhole sample results, a report was received from consultants Aquaterra outlining an initial hydrogeological conceptual model for the Bird-in-Hand mining project area. It includes a preliminary numerical groundwater flow model, which was used to design a pumping test, and predict the effects of pumping. Water resource management is a key issue for the underground mining feasibility evaluation, particularly in relation to mine depressurisation, as the proposed underground mine would extend to at least 500 m depth, well below the water table that is currently at around 30 m depth. It is intended that this report should provide the basis for MXR's discussions with government agencies and the Adelaide and Mount Lofty Ranges Natural Resources Management (AMLNRM) Board, in relation to a proposed application for Ministerial approval to construct and test pump bores designed for abstraction and injection. During the eighth, 2009-2010 project year, no field work was done. A drilling programme planned for the Deloraine prospect on EL 3534 became delayed by the issue of total denial of land access by local property owners, causing MXR to instigate proceedings in the Wardens Court. A judgement in favour of MXR was handed down at the beginning of May 2010, but the landowners still had a right of appeal in the matter. During the ninth, 2010-2011 project year, after July 2010, MXR was able to proceed with its exploratory drilling work on renewed ELs 4303 Lobethal and 4712 Mount Pleasant. Drilling of 7 inclined diamond holes for 2045.7 m undertaken at the Deloraine Goldfield prospect confirmed the extension of mineralisation below the old workings to about 300 m below the surface, or 100 m below the deepest old stopes, and it remains open at depth. Significant mineralised intercepts which were made included 3 m @ 30.3 g/t Au from 310 m downhole in hole DELDDH02, and 1 m @ 12 g/t Au from 216 m downhole in hole DELDDH09. Drilling of 4 inclined diamond holes for 673.6 m undertaken at the Eureka Goldfield prospect to test ground lying immediately beneath the old workings returned a best result of 1 m @ 1.98 g/t Au from 96 m downhole in hole URKDDH01. It would appear that the depth extent of mineralisation here is limited. No significant base metal values were reported from assaying of the drill cores. At both prospects the diamond coring proved to be very difficult and slow, primarily due to the very fractured and broken nature of the ground. During the tenth, 2011-2012 project year, no work was done. During the eleventh, 2012-2013 project year, Terramin Australia Limited purchased the entire project assets from MXR, with effect from October 2013. Five exploration licences covering ~1510 square km now formed the subject ground holding. Activities undertaken by Terramin since it first became involved with the project in July 2013 have included making a re-estimate of the Bird-in-Hand gold resource, preparing a comprehensive scoping study for the Bird-in-Hand Gold Project to identify work needed to progress its design beyond a base case configuration, performing regional reconnaissance surface geochemical sampling, and conducting a compilation of historic data and review of prospects. The resource recalculation, which was done to JORC 2012 standards, was deemed necessary because of the perceived unrepresentative ore sample laboratory density measurements made previously for MXR using pycnometry, a method which did not take into account sample porosity nor the presence of fine vughs within the quartz veins. A revised Indicated Resource estimate of 564 kt @ 13.0 g/t Au for 235,000 ounces of gold was published in October 2013, having been modelled and calculated using Vulcan software into a 3-D block model utilising ordinary kriging estimation, and reported at a 1g/t Au cut-off. A selection of historic Kapunda drillholes was examined by Terramin staff at DMITRE's Glenside drill core storage facility. A total of nine diamond cored holes (KD003, K043, K041, K042, K044, K045, K046, KD002 and KD001) and four open hole percussion holes (KV032, KV038, KV040 and KV031) were inspected. From these holes a total of 188 point spectrochemical analyses were collected using hand-held portable X-ray fluorescence (pXRF) devices. To assist in the review of over 400 historic gold and copper mines located on the newly acquired northern Adelaide Hills tenements, on-ground reconnaissance geochemical sampling was undertaken at the iconic Kapunda copper mine and at Wheal Barton. 16 rock samples were analysed using a pXRF instrument, and another 19 were laboratory assayed. Access was negotiated with Adelaide Brighton Cement Ltd for allowing Terramin to examine and sample the gold mineralisation associated with the Birdwood North clay deposits and with the historic Kitticoola copper-gold mine, to gain insights about the Birdwood and the Palmer goldfields respectively. A total of 69 samples were analysed.