ABM Resources (ASX:ABU) Old Pirate Trenching Program Extends Overall Surface Vein Sampling to 726 Metres Strike Length Averaging 24.01g/t Gold
Perth, Feb 8, 2012 AEST (ABN Newswire) - ABM Resources (
ASX:ABU) is pleased to announce results from Phase 4 (118 samples) of the systematic Old Pirate Bulk Sampling and Trenching Program, which is part of the Company's Twin Bonanza Gold Camp Project. Phase 4 completes the sampling from this program.
Phase 4 trenching results from the northern extensions of the Western Limb Lodes at Old Pirate yielded:
- Phase 4 results average 24.70g/t gold over a combined vein strike length of 144 metres (118 samples) with a peak value of 320g/t gold.
- 30 samples (out of 118 samples) graded greater than 10g/t gold with an average of 88.15g/t gold.
- 9 samples (out of 118 samples) graded greater than 100g/t gold with an average of 187.55g/t gold.
- Individual higher grade vein lengths include:
102 metres strike length vein exposed with average width of 1.1 metres and average grade of 32.62g/t gold including a higher grade vein portion of:
18 metres strike length averaging 104.9g/t gold.
Combined results from Phase 1, 2, 3 and 4:
- 726 metres of combined strike length averaging 24.01g/t gold.
- 799.4 square metres of total vein area exposed with veins up to 6 metres width (averaging 1.1 metre width).
Darren Holden, Managing Director said, "These results from the Old Pirate sampling program have once again extended the system with some spectacular grades. It is remarkable to think that these veins are outcropping at surface or just below the shallow soil profile and, in places, are running in excess of 100g/t gold. This sampling program has proven extremely valuable in providing quality spatial and statistical information relating to the distribution of gold at Old Pirate. The Western Limb Lodes exposed in Phase 4 extend to the north and head under shallow soil cover. Overall the gold anomalism at Old Pirate extends over a 4 kilometre long trend and the possibility of uncovering further veins with detailed exploration work remains a distinct possibility."
Bulk Trenching at Old Pirate
Figure 1 (see link at the bottom of the release) shows the sample location of the Western Limb vein sampling (labelled Phase 4) and the statistics of 118 samples from Phase 4 are shown in Table 1 (see link at the bottom of the release) and combined with Phase 1, 2 and 3 in Table 2 (see link at the bottom of the release). A total of 110 samples were collected from a vein to the west of the main Western Limb vein which was revealed to be an un-mineralised vein and has been omitted from the overall statistics.
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 29% of the mineralised quartz vein samples grade greater than 10g/t gold averaging 73.12g/t gold; and 7% grade greater than 100g/t gold averaging 188.51g/t gold. The overall average of all trench results to date is 24.01g/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. Individual entire veins that are un-mineralised (<1g/t) are excluded from overall statistics.
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 tables and figures, please view the following link:
http://media.abnnewswire.net/media/en/docs/ASX-ABU-577381.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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