Patanella Phosphate Exploration Target
Darwin, June 24, 2014 AEST (ABN Newswire) - Rum Jungle Resources Ltd (
ASX:RUM) is pleased to announce an independently assessed Exploration Target for its Patanella Phosphate Prospect of approximately 50 Mt and 100 Mt at 10% to 17% P2O5 at a cut-off grade of 5% P2O5 or approximately 20 Mt to 50 Mt at 15% to 20% P2O5 at a cut-off grade of 10% P2O5. These estimates are based on broad spaced drilling information of uncertain reliability. The potential quantities and grades are conceptual in nature. There has been insufficient exploration to estimate a Mineral Resource and it is uncertain that future exploration will result in estimation of a Mineral Resource.
Patanella (formerly also called Lucy Creek) on EL 24716 is a rock phosphate deposit on the opposite side of the Georgina Basin from Rum Jungle Resources' flagship Northern Territory Ammaroo Resource (Figure 1 in link below). Patanella is 265 km northeast of Alice Springs, 155 km southwest of the Ammaroo Resource and 100 km south-southeast of Ammaroo South.
Rum Jungle Resources acquired the Patanella Prospect as a result of the take-over of Central Australian Phosphate. While Patanella adds to Rum Jungle Resources' mature phosphate exploration targets, this estimation was undertaken mainly as a necessary prerequisite to applying for more secure tenure over this area. Rum Jungle Resources is currently evaluating if and when any further drilling will be undertaken at Patanella.
History of Discovery and Exploration
Work by CRA in 1992 targeting base metals coincidentally mentioned minor occurrences of turquoise (Cu-Al-Phosphate) on the surface. In the following years, CRA revisited the area, this time targeting unconformity hosted Cu-U mineralisation. They drilled six broad-spaced (500 m) scout percussion holes totalling 530 m. No significant copper or uranium values were returned. However, later review of the assays indicated that some of the holes intersected significant grades and intervals of near-surface phosphorite which was overlooked at the time. In 2006, Arafura Resources drilled several reverse circulation (RC) holes at what became the Patanella Prospect. These holes were principally targeting uranium but intersected phosphate minerals including wavellite (an Al-phosphate mineral). NuPower Resources (later became Central Australian Phosphate) was spun out of Arafura and began phosphate exploration in earnest in 2009. They reassayed the Arafura samples for phosphate using generally 5 m composites. Amongst the reassays reported by NuPower (NUP) on 30th June 2009 were:
- 10 m at 21.7% P2O5 from 30 m in LCRC004 including 5 m at 26.0% P2O5 from 30 m
- 5 m at 21.3% P2O5 from 5 m in LCRC039
- 10 m at 21.7% P2O5 from 5 m in LCRC40 including 5 m at 30.6% P2O5 from 5 m
- 16 m at 15.7% P2O5 from 15 m in LCRC023.
Surface phosphate mineralisation was mapped in putative Red Heart Dolostone (former Errarra Formation) typically 5 m above the contact with the Mount Baldwin Formation. Surface mapping also identified a major fault at the prospect, now interpreted as a growth fault. NuPower drilled 29 RC holes for 1,376 m to determine the tenor and thickness of the phosphatic unit and the thickness of cover. One angled hole targeted the fault zone and wider spaced holes explored for extensions to the north and south along the Red Heart Dolostone-Baldwin contact. The best intercepts based on five metre composites reported by NuPower on 4th March 2010 were:
- 10 m at 22.05% P2O5 from 15 m in LCRC063
- 40 m at 18.09% P2O5 from 15 m in LCRC074 including 10 m at 31.95% P2O5 from 20 m
- 10 m at 17.08% P2O5 from 5 m in LCRC062.
Since taking over as operators, Rum Jungle Resources has undertaken selected resampling and assay of the historic drill samples at one metre intervals for deleterious elements. These assays did not include phosphate and were not included in this estimation.
Details of Exploration Target Estimation
MPR Geological Consultants Pty Ltd estimated the Exploration Target based on six percussion holes drilled by CRA in 1994 and 81 reverse circulation (RC) holes drilled by Arafura Resources and NuPower Resources in 2006 and 2009 respectively for a combined 3,524 m of drilling. The sampling data included a number of apparent inconsistencies which required modification for compilation of the working database used for MPR's study. These inconsistencies reduce confidence in the general reliability of the data.
Drill hole spacing varies from around 100 m by 100 m in central portions of the study area to isolated holes at around 1.0 km spacing in the southern portions. The assayed drilling is dominated by 5 m samples, and combined with the generally broad drill hole spacing these long samples poorly define the potential phosphate mineralisation.
The modelling approach adopted for Patanella is broadly consistent with MPR's recent Ammaroo and Ammaroo South modelling, with differences reflecting the variability in mineralisation and drill hole spacing.
The mineralised domain used for the current study captures one-metre down-hole composites grading greater than 5% P2O5 and is extrapolated a maximum of around 500 m from drill holes. It trends northeast over approximately 6.2 km with an average width of around 1 km. Interpreted thicknesses range from approximately 3 m to 42 m and average around 8 m. The mineralisation rarely outcrops and is overlain by an average of around 23 m of un-mineralised material.
For the block model constructed for the current review, grades were estimated by Ordinary Kriging of one metre down-hole composites within the mineralised domain. Prior to estimation the mineralised domain composites were unfolded to remove the gentle undulations from the mineralised domains. The Kriged estimates were re-folded to their correct positions in the final block model.
No density information is available for Patanella. The current estimates include a density of 1.7 t/bcm consistent with the value adopted for the Ammaroo on the basis of immersion density measurements of diamond core. Applicability of this value to Patanella is uncertain.
The broad drill spacing and uncertain representivity of the available sampling prevents estimation of Mineral Resources for Patanella.
Drilling requirements for estimation of Mineral Resources for Patanella are unclear and Rum Jungle Resources is evaluating its options. To provide a first pass indication of potential drilling required for estimation of Mineral Resources a 400 m by 400 m pattern was overlain on the current mineralised domain interpretation. This spacing is consistent with the drilling used for estimation of Inferred Mineral Resources at other RUM phosphate projects.
With projection to an average of four metres below the interpreted base of mineralisation the 400 m by 400 m pattern comprises 80 holes for approximately 2,700 m of drilling. This pattern makes no allowance for existing drilling on the basis of the assumption that the sample intervals and apparent data reliability are inappropriate for confident resource estimation. Although not necessarily sufficient for Mineral Resource estimation, a subset of such a drilling pattern may be sufficient to test the general validity the current Exploration Target, and yield an updated Exploration Target.
The tables in link below describe the Patanella drilling and Exploration Targets.
To view all figures and tables, please visit:
http://media.abnnewswire.net/media/en/docs/ASX-RUM-407827.pdf
About Verdant Minerals Ltd
Verdant Minerals Ltd's (ASX:VRM) strategic intent is to create shareholder value through the discovery, development and operation of fertiliser and industrial mineral projects, located in close proximity to existing transport infrastructure, with a primary focus on the Northern Territory of Australia.
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