Euro Manganese Inc.’s (EMN) principal focus is advancing the evaluation and development of the Chvaletice Manganese Project, in which it holds a 100% interest through its Czech subsidiary, Mangan Chvaletice s.r.o.
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Summary:
Due to grinding and flotation processes, none of the original textures that would have characterized the in situ rocks will have been preserved in the tailings material.
The mineralization found in tailings at the CMP has been deposited by manmade processes following grinding and flotation processes of black pyritic shale and is therefore not characteristic of a traditional manganese deposits. The material can be physically characterized as a compacted soil, with varying degrees of particle sizes from clay to coarse sand.
There is sorting of the flotation waste by grain size and weight, resulting from the sedimentation from the edge to the center of the tailings deposit.
Subsequently, three zones of grain sizes in the tailing pond can result with:
- An outer zone of fine-grained sand and silty sand
- A central zone of alternating sandy laminae with the outer and inner zone types
- An inner zone comprised of silt to slightly clayey silt (finest material of all zones).
This zoning is typical for slurry tailings and results from sedimentation of deposited slurries from fluctuation of water levels during decantation operations (removal of water) within the central zone and a gentle slope (1.5%), leaving little to no water in the outer zone.
The Chvaletice bedrock deposits of iron and manganese mineralization constitutes one horizon in the metasedimentary stratigraphy with variable proportions of carbonate and silicate minerals occurring laterally from west to east. Through mineral processing during historical mining operations, these minerals have been reduced in size and partially blended by grinding and flotation processes.
Through depositionary processes, these mineral particles were distributed throughout the tailings facilities by sedimentation from suspension in a tailings slurry. Thin beds of sediment will have been deposited laterally with a gradation from coarse to fine particles away from the point of deposition. It is then interpreted that grain size and moisture content may have more similarity with materials in a vertical sense and have more variability in a lateral sense. Whereas, mineral and grade distribution, being related more to the process rather than deposition, is interpreted to have more similarity with materials in a lateral sense and less direct similarity with materials in a vertical sense. However, a relationship exists between elevated manganese grade with coarser particle size.
Met-Solve completed x-ray diffraction (XRD) and scanning electron microscopy (SEM)-energy dispersive x-ray spectroscopy (EDS) analyses on behalf of EMN in 2015 using the samples collected from test pits in 2015. The analysis identified the main manganese bearing minerals were rhodochrosite (MnCO3), and kutnohorite (Ca(Mn2+ , Mg, Fe2+)(CO3)2) which forms a series with dolomite and ankerite. These were classified as the principle manganese (Mn)-carbonate minerals. Additionally, the presence of trace quantities of manganese- silicates such as sursassite (a manganese bearing sorosilicate), and oxides such as pyrolusite (a manganese dioxide (MnO2) and kurchatovite (calcium-magnesium-manganese-iron borate (Ca(Mg, Mn, Fe2+)B2O5) were identified. Pyrite was noted to be the primary form of sulphide mineral, with concentrations in the samples between 5 to 9%. Gangue mineralogy consists of primarily quartz with moderate amounts of plagioclase, feldspars, micas, and apatite. Low concentrations (less than 5%) of kaolinite clay mineral was identified.
Further mineralogy work conducted on a bulk sample by CRIMM on behalf of EMN in 2017, concluded that manganese occurs with variable proportions of iron, calcium, and magnesium with carbonate to form a wide variety of manganese bearing carbonates from the rhodochrosite-siderite-dolomite-calcite spectrum. The work concluded that 80% of the manganese occurred as carbonate and 19% of the manganese occurred as silicate. High concentrations of iron and phosphorus were identified in the gangue minerals which were contained predominantly in pyrite and apatite, respectively.
Whole rock lithogeochemical analysis conducted on Sonic drill samples collected during the 2017 program measured total sulphur concentration in the tailings with an average of approximately 3.1% which is sourced form sulphide, sulphate and organic origin. Total carbon concentrations averages approximately 3.4%, which includes contributions from graphite, organic and carbonate origin.