Potash West NL (ASX: PWN) is pleased to announce it has obtained promising results from the recently completed aircore drilling programme on its E70/3100 licence, which is located on the western margin of the prospective Dandaragan Trough and 100km north of Perth.
The maiden drilling programme involved a total of 7 widely spaced holes for 534m along road verge traverses, (Figure 1). Holes were located to provide stratigraphic information on the prospective Coolyena Group sediments which host potash mineralisation in glauconite rich sediments, known as greensands, elsewhere on the Company’s tenure.
Potash West is exploring the Dandaragan Trough to evaluate the commercial potential of the greensand deposits. These have been examined as a source of potassium several times over a period of nearly 50 years but not pursued due to low Potash prices. Current prices and technological advances make re-examining the area attractive.
The drilling represents the first stage in the investigation of the Cretaceous stratigraphy of the Dandaragan Trough where Potash West controls almost 3,000km of tenements. Lithologies of the Coolyena Group, which host various glauconite rich units, are poorly exposed in E70/3100. The aim of the programme was to test the prospective stratigraphy over wide areas of the tenement and to collect samples for the initial phases of metallurgical testwork.
Holes were located to provide maximum information over the almost 50km length of E70/3100 and did not specifically target interpreted areas of favourable geology. In this context the widths and grade of the intersections are encouraging particularly compared with published results. Analyses of samples from drillhole DGH2, drilled by the Geological Survey of WA near Dandaragan in the 1960s, reported 2.3% KO over a thickness of 21m of weathered Poison Hill Greensand, below which 12m of the fresh formation averaged 5.4% KO. DGH2 is located some 10km northeast of the northern boundary E70/3100. (Fig 1).
All seven drill holes penetrated significant thicknesses of Coolyena Group sediments. The lithologies consist of fine to medium grained sandstones, siltstones and claystones containing varying amounts of glauconite visible in drill chips. Composited 2m intervals with KO assays above a cut off grade of 2% are shown in Table 1.
|Hole||Depth (m)||East(m)||North (m)||Surface Level (m)||interval (m)||From (m)||to (m)||K2O%|
1. Drilling by aircore method
2. Some samples collected below water table
3. All holes drilled vertical.
4. Stratigraphy is flat dipping – downhole intersection widths approximate the true width of the mineralisation
5. Samples are collected through a rig rotary splitter over 2m intervals and geologically logged.
6. Total sample preparation, assays by lithium borate fusion XRF
7. Composite intervals have been determined with regard to geological description using a lower cut off grade of 2% KO
8. Drill holes have been located by hand held GPS methods using the MGA94 Zone 50.
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The Project comprises 10 exploration licences, located between 50 and 230 km north of Perth, in Western Australia. These tenements lie between two major road transport corridors: the Brand Highway to the west, and the Great Northern Highway to the east.
The Dampier-to-Bunbury gas pipeline passes along the western boundary of the Project, as does a major power transmission line.