Tin Mineralisation in the Mesoproterozoic Prospect Hill Region, Northern Flinders Ranges: Recent Drilling Results and Suggestions for Regional Tin Exploration in South Australia UNCOVER CURNAMONA 2017 Graham S. Teale & Adrian M. Brewer Teale & Associates Pty. Ltd., Brewer Geological Services
Acknowledgments Much of the new data for this presentation was gathered by the authors during the current exploration joint venture with Havilah Resources Ltd. PACE funding (DPY09-12 Prospect Hill, 2017) is gratefully acknowledged. Historic data obtained during exploration work by the authors for numerous other companies, from 1982 until the joint venture with Havilah Resources Ltd in 2007, has also been drawn upon. The authors would like to thank Havilah Resources Ltd for permission to give this presentation.
Competent Persons Statement The information in this presentation that relates to Exploration Targets, Exploration Results and Mineral Resources is based on data compiled by geologists, Graham Teale and Adrian Brewer, who are Competent Persons and who are members of The Australian Institute of Geoscientists. Both Graham Teale and Adrian Brewer have sufficient experience, which is relevant to the style of mineralisation and type of deposit and activities described herein to qualify as a Competent Person as defined in the 2012 Edition of Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves. Messrs Teale and Brewer consent to the inclusion in the presentation of the matters based on their information in the form and context in which it appears. This information was prepared and first disclosed under the JORC Code 2004. It has not been updated since to comply with the JORC Code 2012 on the basis that the information has not materially changed since it was last reported.
Prospect Hill - Location
Geology Mineralisation discovered in 1980. South Ridge Deposit contains an Indicated Resource of 302,000 tonnes @ 0.64% Sn to 90 metres vertical depth (non JORC compliant). Mineralisation (South Ridge) open at depth on the western end (PHRCO37, 5m @ 0.85% Sn: 2007) and eastern end (PHRCO29, 10m @ 0.48% Sn). No deep drilling as yet. A new resource is currently being evaluated with the South Ridge Deposit extended to the west (west of PHRC037) by a further 400m during recent drilling. Mineralisation is considered to be intimately associated with fluids derived from the Prospect Hill Granite and emplaced into comagmatic silicic pyroclastics.
PROSPECT HILL Uranium Channel Airborne Radiometrics and Geochemistry Stream Sediment Geochemistry Sample site >70 >32 W : ppm >500 >100 >40 Sn : ppm 0 1000 2000m
Significant Tin Intersections - Southern Ridge Prospect PHP02 6m @ 1.85% PHP05 9m @ 0.99% PHP15 6m @ 2.33% PHRC03 3m @ 4.85% PHRC04 10m @ 1.16% PHRC23 9m @ 0.93% PHRC24 8m @ 1.48% Significant Tin Intersections - Recent PACE Drilling PHRC54 3m @ 0.2% PHRC55 3m @ 0.79% 4m @ 0.69% 5m @ 3.32% PHRC56 1m @ 0.34% PHRC57 3m @ 0.11% 4m @ 1.03% PHRC59 1m @ 1.38% 1m @ 0.77%
South Ridge mineralisation - cassiterite and gangue Zn biotite gahnite garnet cassiterite Mag. x 100; length of photomicrograph = 1.3mm; PPL PHRC03 44m-45m Mag. x 50; length of photomicrograph = 2.6mm; PPL PHRC03 45m-46m F-margarite cassiterite garnet cassiterite scheelite Mag. x 100; length of photomicrograph = 1.3mm; PPL PHRC04 35m-36m Mag. x 50; scale bar= 200µ; PPL PH32
Black Rock mineralisation - slab photos Be-rich domain cassiterite Sample 20055 57.7% Sn High grade Sn-bearing samples can be easily located if extreme grade. However, below ~20% Sn it is difficult to identify Sn-bearing lithotypes (see sample 20053 adjacent). FPXRF is of use here. Sample 20053 16.1% Sn
White Well Granite - 506ppm Sn, 33ppm Th, 77ppm Y, 12ppm U Old Hut granite - 37ppm Sn, 187ppm Th, 162ppm Y, 78ppm U ovoidal K-feldspar megacryst ovoidal tourmaline aggregate North Ridge granite - 35ppm Sn, 31ppm Th, 61ppm Y, 14ppm U Prospect Hill Granite Porphyry - 18ppm Sn, 175ppm Th, 130ppm Y, 50ppm U
Prospect Hill Granite porphyry showing tourmaline nodule encapsulated in quartz. The tourmaline nodules are enriched in U (up to 340ppm), Th (up to 1600ppm), Bi (up to 100ppm) and Zr (up to 740ppm), far in excess of the host granite (FPXRF).
Exploration Ramifications Granitic intrusives are high level to sub-volcanic and are extremely fractionated with low Nb/Ta and Zr/Hf ratios. Associated mineralisation also exhibits low Nb/Ta and Zr/Hf ratios (6 and 7.8 respectively at Black Rock prospect). Intrusives also contain high concentrations of Y, Th, U, Sn and Pb These geochemical characteristics may be used as pathfinders to potential regional host domains. The intrusives and associated volcanics are ~1555Ma, younger than the known hosts of Gawler and Curnamona Cu-mineralisation (1575Ma-1600Ma). These intrusives and extrusives are viewed as a late lower crustal melting phase and share similar ages to metamorphic/metasomatic events in the Mt. Woods-Coober Pedy area, the Mount Painter region and the SE Yorke Peninsula area. Similar aged intrusives are present in the Mt. Woods area and it may be possible that Sn and associated mineralisation in the Central and Southern Gawler Domain may be associated with similar aged intrusives.
The mineralisation is associated with anomalous Bi, REEs, U, W, Cu and F. Any anomalous grouping of these elements in a regional soils programme should be viewed positively, especially Bi. The FPXRF does not detect coarse (>0.2mm) cassiterite in soils and streams, with anomalous Sn in soils detected when cassiterite grain size is between 20µ and 60µ. Original -40+80 mesh stream anomalies have proved to be accurate and in need of follow up even when detailed FPXRF in nearby soils has been ineffective. Because of the general lack of sulphides in the mineralisation the Sn lodes can be very difficult to locate and further delineate. Geophysical techniques (IP, EM, magnetics), would not locate the mineralisation.