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 (based on other tailing pond borehole sludge studies (Novotny et al. 1972). 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, and

- 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 (Bateria Slany, Chapter 2 1989).

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.

Milos et al. (2018) conducted a comparative evaluation of various tailings extraction and transportation methods. The methods evaluated include excavators and trucks, hydromonitoring, conveyors, and pipelines for transport. The following points have been extracted from Milos et al. (2018) on the benefits of the use of excavators and dump trucks for tailings extraction:

- Transport by dump trucks provides flexibility and enables operational increase in or decrease of the mined tonnage.

- Breakdown is easily solved by using back-up capacity of dump trucks or by sub-contractor, at extraction operation or at rehabilitation.

- Dump trucks are used for both, tailings extraction and rehabilitation.

- Tailings extraction is very flexible as an excavator along with the dump truck fleet can be moved operatively according to head grade requirements.

- Dry ore and dry tailings stockpiles require smaller areas and capacity may be temporarily increased by stockpiling ore at the mine site.

- More economic water management, water remains in the processing plant, contamination of the tailings extraction operation and the rehabilitation area is limited.

The use of excavators and dump trucks to extract and transport the tailings to the mill is the selected method.

Tailings extraction using excavators and trucks will take place in 5 m high benches, with berms a minimum of 20 m wide, and bench faces angled back to 45° to ensure stability during the tailings extraction. Milos et al. (2018) completed geotechnical evaluations and in accordance with Czech legislation established that benches must have a minimum safety factor of 1.1.

The CMP process plant is designed to have a 25-year project life at a nominal production rate of 48,000 t/a of HPEMM by extracting approximately 1.1 Mt/a of the CMP tailings. Two-thirds of the annual HPEMM flake production is expected to be converted into approximately 100,000 t/a of HPMSM. HPEMM product containing greater than 99.9% manganese is expected to be sold as flakes and powders and is planned to be produced without the use of selenium and chromium. The CMP HPMSM product will be designed to contain no less than 99.9% MSM, a minimum of 32.34% manganese, and will be sold in powder form, produced without the use of fluorine. The proposed process flowsheet was developed based on the various test results, including a comprehensive testwork program with semi-continuous pilot plant testing. The flowsheet includes following key process circuits:

- CMP tailings pulping

- Wet magnetic separation to upgrade the leach feed from 7.33% tMn to approximately 15% tMn and on average reject approximately 57.7% of the feed to NMT, with an expected 86% manganese recovery

- Sulphuric acid leach to dissolve the acid leachable manganese, mainly from the manganese carbonate minerals

- Leach solution purification, including magnesium content management in anolyte solution, to ensure efficient electrowinning operations and high- quality products

- Washing of LR using a five-stage CCD washing, including manganese and ammonia recovery from washing solution to minimize their losses and produce washed leach residues for superior environmental performance.

- Manganese electrodeposition from qualified solution to produce HPEMM product, including post- electrowinning treatments and handling, such as chromium-free HPEMM plate passivation, washing, stripping and stripped plate handling

- Acid dissolution of HPEMM flakes, leach solution, deep purification, crystallization by evaporation and crystal drying to produce HPMSM

- Dry stacking of non-magnetic separation tailings and washed leach residues onto the lined RSF.

The flowsheet and equipment proposed for the CMP have been widely used in the manganese metal and sulphate industry and it is expected that the equipment can be operated and maintained effectively in the local environment. Further optimization of the flowsheet, equipment sizing, and layout should be conducted.