ABM Resources NL (ASX:ABU) Announces Old Pirate Gold Program Phase 2b Bulk Longitudinal Trenching Results
Perth, Dec 22, 2011 AEST (ABN Newswire) - ABM Resources NL (
ASX:ABU) is pleased to announce results from Phase 2b (125 samples) of the systematic Old Pirate Bulk Sampling and Trenching Program, which is part of the Company's Twin Bonanza Gold Camp Project.
- Phase 2b results averaging 20.44g/t gold over a combined vein strike length of 145 metres (125 samples) with a peak value of 293g/t gold.
- 33 samples (out of 125 Phase 2b samples) graded greater than 10g/t gold and averaged 66.99g/t gold.
- 8 samples (out of 125 Phase 2b samples) graded greater than 100g/t gold and averaged 164.88g/t gold.
- Individual veins exposed range from 0.4 to 3 metres in width (averaging 1.0 metre).
- Combined Phase 1, 2a, and 2b show overall results of:
1,691.4kg surface vein material sampled with a combined total strike length of 427 metres and a weighted average of 21.85g/t gold.
Eastern Limb Lodes combine to:
248 metres of strike length from 5 overlapping veins averaging 23.96g/t gold including individual veins with:
83 metres strike length averaging 56.31g/t gold*
68 metres strike length averaging 25.86g/t gold
12 metres strike length averaging 115.1g/t gold*
30 metres strike length averaging 26.58g/t gold*
Western Limb Lodes include individual vein lengths:
26 metres strike length averaging 21.80g/t gold
10 metres strike length averaging 78.28g/t gold*
46 metres strike length averaging 10.59g/t gold*
25 metres strike length averaging 8.50g/t gold*
(*) Refers to previously reported results which are unchanged with extensions of vein sampling in Phase 2b.
- A further 419 longitudinal strike length trench samples and 481 costean samples (across the vein) pending assay and compilation along with duplicate samples.
Darren Holden, Managing Director said, "The longitudinal surface sampling at Old Pirate continues to return spectacular grades. Old Pirate is devoid of historic diggings, was missed in the old gold rush days and likely represents one of the last high grade vein systems discovered outcropping at surface on the Australian continent. The process of longitudinal sampling is designed to solve the statistical nugget effect of the coarse and unevenly distributed gold and is providing new insights into the distribution of gold within the individual veins. In particular the Eastern Limb Lodes are shaping up as a composite series of stepping veins with considerable strike length and remains open along strike to the north."
Bulk Trenching at Old Pirate
Figure 1 (see link at the bottom of the release) shows the sample location of the Phase 1 and Phase 2a (refer announcements 13/10/2011, 29/11/2011) and Phase 2b bulk longitudinal (strike-length) trenching at Old Pirate. Phase 2 was split into two batches for processing at the laboratory. A further 419 samples of Phase 3 and duplicate samples of all Phases along with 481 cross-trench samples (costeans) are being analysed and compiled. The statistics of all 125 samples from Phase 2b are shown in Table 1 (see link at the bottom of the release). Table 2 (see link at the bottom of the release) shows the combined statistics from Phases 1, 2a and 2b.
About the Old Pirate High-Grade Gold Prospect
The high grade Old Pirate Gold Prospect is located approximately 1,800 metres from the 1.67 Moz Buccaneer Porphyry Gold Inferred Resource. Gold at Old Pirate is distributed throughout a series of quartz veins within interlayered sandstone and shale sedimentary rocks. The veins range from centimetres to several metres wide and are defined by drilling, surface mapping and trenching over an area of 600 metres by 250 metres and to a depth of 200 metres within an overall anomalous trend in excess of 3 kilometres. The veins and sediments are folded into a plunging anticline (an arch shaped geological structure). In addition a diorite intrusive rock has been emplaced within the sedimentary rocks and is thought to have been a focus of the mineralising fluids. Previously ABM had contracted Dr Charles Butt of the CSIRO in Perth to conduct preliminary Scanning Electron Microscope Analysis work on surface gold samples and Dr Butt concluded that, based on the samples provided, the gold in the veins is not supergene enriched and is hence primary gold in quartz (refer ASX announcement 15/11/2011).
Due to the uneven distribution of the gold within the quartz veins, ABM geoscientists focus on the location and distribution of the actual veins as well as the gold within the veins. Based on the trenching results to date approximately 27% of the quartz vein samples grade greater than 10g/t gold averaging 71.33g/t gold; and 6% grade greater than 100g/t gold averaging 211.68g/t gold. The overall average of all trench results to date is 21.85g/t gold.
Rationale and Sampling Method
ABM has previously drilled several high grade intercepts including 9 metres averaging 100.9g/t gold and 5 metres averaging 274g/t gold interspersed with generally lower grade intercepts. The gold can be coarse (up to 2 to 3mm grains) at Old Pirate and is hosted within quartz veins. However, the distribution of the gold within these veins is not uniform, and hence drilling will likely under-call the overall grade due to the fact that there is a less than 1 in 3 chance of intersecting high grade in any particular part of the vein. Upon advice from external consultants, rigorous and systematic bulk sampling of the quartz along the strike length of veins at Old Pirate was proposed, of which the on-going work is presented here. This information, along with statistical parameters and extents of mineralisation, will be used to determine the minimum drill spacing required for further resource work.
The process for the bulk-trenching program is:
1. Natural outcropping veins are mapped for location and width and sampled at 1 metre intervals.
2. The backhoe digger then digs a trench that exposes those parts of the veins that are hidden underneath shallow soil cover to provide a combined map of natural outcrop and trench exposed quartz vein.
3. For each metre of exposed quartz vein (both in natural outcrop and trenched veins) two representative samples of approximately 3 to 4kg are collected. Quartz is selected systematically so as not to bias individual samples. One sample is sent to the laboratory with the remaining sample retained for future checking.
4. The sample width depends on the width of the vein. In cases where the vein width is greater than 1 metre, multiple samples are collected across the vein.
5. The maximum depth of the trench is 60cm (due to permit regulations, safety considerations and to minimise environmental impact). If the soil cover is greater than 60cm then sampling does not take place.
6. Samples are processed by ALS Global in Alice Springs (NT), ALS Global in Orange (NSW) and ALS Global in Perth (WA) where they are weighed and analysed using regular fire assay.
Samples greater than 10g/t are re-assayed using AA25 ore-grade method, and samples >100g/t are re-assayed using AA25 / Over Limit Dilution method.
7. Overall statistics and spatial distribution for vein strike length and grade are calculated by measuring sampled portions of vein (including a projection of short lengths (<10 metres) where the vein is inferred to have extended under cover) and then averaging all of the samples along the length.
8. Samples were originally surveyed with a hand-held GPS and re-surveyed with a differential GPS (20cm accuracy).
About the Twin Bonanza Gold Camp
The Twin Bonanza Gold Camp is centred approximately 22 kilometres south of the Tanami Road and 14 kilometres east of the Western Australia - Northern Territory border. The Project spans the highly prospective "Trans Tanami Structure" an inferred regional / tectonic geological feature which hosts numerous gold deposits including Newmont's multi-million ounce Callie Gold Mine. In 2010 ABM focused its effort at Twin Bonanza on the Old Pirate Prospect - a 3 kilometre anomaly with multiple high-grade zones in quartz veins hosted in sedimentary rocks and the Buccaneer Porphyry Gold Deposit - an intrusive related bulk tonnage gold deposit where the Company reported a 1.67Moz gold maiden resource in February 2011. In 2011 ABM has reported several extensional discoveries around Buccaneer including the Cypress, Caribbean, Empress and Eastern Contact Zones as well as high grade gold in drilling and trenching at Old Pirate. The Company aims to complete a revised resource in the first quarter of 2012.
For the complete ABM Resources announcement including figures and tables, please view:
http://media.abnnewswire.net/media/en/docs/ASX-ABU-572398.pdf
About ABM Resources NL
ABM Resources (ASX:ABU) is developing several gold discoveries in the Central Desert region of the Northern Territory of Australia. The Company has a multi-tiered approach to exploration and development with a combination of high-grade production scenarios such as the Old Pirate High-Grade Gold Project, large scale discoveries such as Buccaneer, and regional exploration discoveries such as the Hyperion Gold Project. In addition, ABM is committed to regional exploration programs throughout its extensive holdings including the alliance with Independence Group NL at the regional Lake Mackay Project.
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