"2 - given the length of the strike is it not likely that there would be a few large pods of high grade somewhere in there? Very unlikely in my opinion in manganiferous shales. It would be a different story if you were in dolomites and altered cherts (eg Woodie Woodie model). Whatever you do dont think this area is comparable to Woodie Woodie, they are very different mineralisation models."
From ARM annoucements (emphasis added):
"The manganese at Jessica Bore is hosted in a dolomitic unit which can be traced over at least 60km of strike within the Talga Fault Zone, all within Auroras tenements. This indicates that, in addition to Jessica Bore, 60km of strike of the fault is highly prospective for high grade manganese. The Jessica Bore manganese mineralization is in a similar host rock (dolomite) and of a similar geological age (Mid Proterozoic) to the major Woodie Woodie manganese deposits, located 500 km to the NE, in the northeast extension of the Bangemall Basin, and also appears to have similarities to the manganese deposits at Bootu Creek in the Northern Territory, Australia."
"The main host rocks identified are siltstones and dolomites of the Ullawarra and underlying Devil Creek Formation, in particular a zone approximately 30km long and 4kms wide as shown in the accompanying maps.
(in reference to Mango 9) "This year massive manganese mineralisation has been identified forming strike parallel lenses and pods along the crest of a NW-SE ridge; four lenses between 70m and +200m long are strung over a 550m zone mapped and were observed to continue beyond this. Widths on surface are 10m to 25m but true thickness may be less."
"Geologically the host rocks are thinly laminated siltstones, shales and cherts of the Ullawarra Formation..."
Take a look at the full list of April 2009 RockChip Samples. All the high grades are coming from the massive Mn oxide layer. The grades in the adjacent less altered shales are much lower. It is clear from photos on several announcements that the massive Mn oxide layer is both contiguous and has a true width of at least 2m in several of the propects ARM have targetted.
Also plenty of chert and dolomite (admittedly later annoucements seem to indicate it is the formation underlying the Ullawarra) present.
ARM Price at posting:
97.5¢ Sentiment: LT Buy Disclosure: Held
