The hydrometallurgical work was performed on composite samples from the McGregor Pit
area, American Manganese provided in 5 buckets. Each bucket was riffled and split to
ensure homogeneity and representative samples were collected, pulverized and sent for
whole rock analysis (lithium borate fusion followed by XRF) at ALS Chemex in North
Vancouver, Canada. The manganese content varied between 8% and 10.6%, while the iron
content was constant at 2.3%. A complete analysis of the samples is given in Table 3.
Check assays were performed at ACME (Global Discovery Labs) and Assayers Canada in
Vancouver, Canada, by whole rock analysis and four acid digestion / ICP, respectively (data
provided in Table 4). The whole rock analysis method gave consistent results, with ALS
Chemex yielding slightly higher results. The four acid digestion method reported significantly
lower manganese grades, indicating incomplete digestion.
The ore sample with the highest manganese grade (bucket R4) was chosen for most of the
subsequent hydrometallurgical scoping work.
Previous reports produced by Mountain States R&D International Inc. in Vail, Arizona, USA
and PRA – Inspectorate, in Richmond, BC, Canada revealed that the ore is friable and
mechanical agitation during slurrying produces significant amounts of fines that impede
filtering and/or settling. The fine material, associated with clay and silt was believed contain
little or no manganese, and removing the fine particles prior to leaching would lead to minor
manganese losses. To investigate this hypothesis, a particle size analysis was performed
on a representative sample weighing approx 1.5 kg removed from bucket R3. The various
particle size fractions were then analyzed to determine whether manganese concentrates or
not in the material with PS > 2 mm (10 mesh), as initially believed. The particle size analysis
and the corresponding manganese assay for each of the particle size fractions are tabulated
in Table 5. As seen in Table 5, the material with particle size larger than 2 mm contained
more than 9.6% Mn, the manganese content dropping as the particle size decreased.
However, even for the fraction with particle size below 60 mesh, the manganese content
was still relatively high (6.5-6.8%) and the removal of the < 60 mesh fraction would mean
losing about 18% of the total manganese content."
https://www.portable-crusher.org/showroom/index.php/archives/314
Not sure if it's old material ... just seen it posted today.