Mt Chester Manganese Project - Ravensthorpe Joint Venture
Introduction
Ravensthorpe Joint Venture tenements and project locations
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Mt Chester Manganese Project
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The Mt Chester Prospect is within the Ravensthorpe JV Project, a joint venture between Pioneer (75% interest) and Galaxy Resources Limited (25% contributing interest).
During 2008 the focus of the joint venture shifted away from copper gold mineralisation to manganese following the discovery of a manganese rich horison within the Chester Formation that returned rock chip samples up to 45% Mn.
Mt Chester Manganese Project
Why Manganese?
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The project is located within the Archaean Age Chester Formation which comprises a sequence of siltstones, shales, massive pyrite beds and Banded Iron Formations.
The joint venture holds tenure to an approximate six (6) kilometre strike length of prospective stratigraphy that has been subjected to minor review for manganese mineralisation.
Chester Manganese Project cross section
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Prospectors discovered the manganese horizon within the Ravensthorpe Ranges over 100 years ago and a adit was excavated through the hill at the Mt Chester Prospect to sample the horizon approximately 30 m below the surface outcrop as a possible source for flux for a nearby copper smelter.
During the 1990s Metana Metals NL completed 5m composite chip samples along the length of the adit assaying for gold, copper, and manganese. The manganese horizon averaged 15 m at 17.7% Mn, including 5m at 21.6% Mn.
Work completed by the joint venture includes preliminary mineralogy of samples taken from remnant adit stockpiles. The dominant manganese mineral has been identified as Pyrolusite which is the preferred mineral for smelters as it produces a good lump product and therefore attracts premium prices.
Other work has included rock chip sampling and soil sampling that has traced the manganese horizon along a strike of approximately 600m.
Chester Manganese Project surface topography and manganese sampling
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Based on the data currently available the joint venture believes the mineralisation is likely to be due to preferential hydrothermal replacement of either a shale or dolomitic horizon within the Chester formation.
The table below shows significant results for the rock chip samples:
| Sample ID | East (m) | North (m) | Mn (%) | Fe (%) | SiO2 (%) | P (%) | S (%) |
|---|---|---|---|---|---|---|---|
| RMP17 | 234,927 | 6,278,173 | 49.00 | 9.46 | 2.28 | 0.02 | 0.03 |
| RMP22 | 235,124 | 6,277,969 | 45.93 | 9.81 | 3.34 | 0.02 | 0.03 |
| RMP39 | 235,182 | 6,277,911 | 41.72 | 9.26 | 7.25 | 0.01 | 0.04 |
| RMP31 | 235,181 | 6,277,931 | 40.43 | 11.35 | 4.67 | 0.01 | 0.04 |
| RMP08 | 235,102 | 6,277,987 | 40.17 | 17.89 | 3.60 | 0.02 | 0.02 |
| RMP04 | 235,107 | 6,277,987 | 39.78 | 11.29 | 10.80 | 0.02 | 0.03 |
| RMP21 | 235,113 | 6,277,980 | 37.62 | 15.59 | 6.97 | 0.02 | 0.04 |
| RMP18 | 234,923 | 6,278,187 | 37.31 | 17.64 | 6.42 | 0.02 | 0.07 |
| RMP27 | 235,179 | 6,277,924 | 36.65 | 10.96 | 7.99 | 0.01 | 0.04 |
| RMP16 | 234,968 | 6,278,123 | 35.58 | 15.62 | 12.41 | 0.04 | 0.04 |
| RMP28 | 235,168 | 6,277,913 | 35.27 | 13.11 | 8.73 | 0.01 | 0.04 |
| RMP29 | 235,170 | 6,277,917 | 34.06 | 13.91 | 8.93 | 0.01 | 0.05 |
| RMP58 | 235,121 | 6,277,974 | 33.77 | 18.20 | 12.01 | 0.03 | 0.08 |
| RMP32 | 235,184 | 6,277,924 | 33.41 | 15.89 | 6.91 | 0.01 | 0.06 |
| RMP30 | 235,186 | 6,277,929 | 32.01 | 11.94 | 9.80 | 0.01 | 0.03 |
The joint venture has permits in place to complete up to 12 drillholes which will test as a priority an initial 200m strike length of mineralisation. Drilling will target the down dip projections of outcrop near the adit and beneath a surface costean. Material will be used to appraise the beneficiation characteristics of the mineralisation.
The joint venture was attracted to the Mt Chester Prospect because of the high manganese grades evident over significant widths (potentially in the order of 10-15m). In addition, it is close to established infrastructure at Ravensthorpe and is within 180 km of the Esperance Port.
The project is within the Ravensthorpe Ranges which is an environmentally sensitive area. Pioneer employs industry best practice procedures when working in such areas.
Copper Gold Exploration
Elverdton-Desmond long section
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The joint venture has completed a significant amount of work evaluating the potential of the Elverdton-Desmond copper gold workings.
The copper gold workings occur within en-echelon shear zones in Archaean host rocks on the northern flanks of the Manyutup Tonalite. The shear zones can be up to 1km long and 30m wide, but are disrupted by later faults and dykes, forming complex, usually narrow, mineralised shoots 30m to 300m in strike. Copper occurs within disseminated to massive, chalcopyrite-pyrite-pyrrhotite-magnetite-gold-mineralised lenses.
Reverse circulation and diamond drilling completed by the joint venture along the strike and below the old working indicates that the development of copper mineralisation within the shear zone is erratic and strongly shoot controlled. It is unlikely to support a stand alone mining operation.
Potential exists in the vicinity of the Desmond working for a small open cut resource but at the current time the joint venture is focused on manganese exploration.
