METALLURGICAL SERVICES
Metallurgical services include:
 | BENCH TESTS |
| PILOT PLANTS |
| PRELIMINARY FEASIBILITY STUDIES |
BENCH TESTS
The bench test is usually the first step in the development of a metallurgical process. Typically, a 24 to 48 hour sodium cyanide agitation leach is conducted as an initial measure of response for treatment of precious metal ores. A standard flotation test is conducted if base metal sulfide ores are involved. Gravity concentration or sink-float testing may also be utilized. If the response to conventional methods is unsatisfactory, metallurgical diagnostic tests are conducted which measure the chemical interaction of its constituents and determines the characteristics primarily responsible for the refractory nature of the ore. More elaborate laboratory processing methods may be utilized. The bench test data generated are used for process development, flowsheet design as well as the development of a prefeasibility study.
Bench testing capabilities include:
| Crushing and grinding tests for liberation. |
| Rougher flotation followed by cleaner and recleaner flotation on 500 to 2000 gram charges. |
| Locked-cycle testing on four to eight, 10,000 gram charges. |
| Selective flotation testing. |
| Flotation tests on concentrates. |
| Thickening tests on concentrates and tailings. |
| Agitation leaching by bottle roll or vari-speed propeller agitation. |
| Heap leach or vat leach columns from one to twenty kilograms. |
| Autoclave leaching one liter volume at 2,000 psi maximum and 400oC maximum. |
| Carbon-in-pulp continuous staging, carbon-in-leach, carbon adsorption. |
| Chlorination treatment of agitation leach pulps or concentrates. |
| Electrowinning from strip solutions. |
| Mechanical panner by revolving spiral. |
| Drum and amalgamations from one to fifty kilograms. |
| Roasting of products usually followed by leaching. |
| Sintering of materials for the generation of specific products. |
| Micro and macroscopic examination of test products such as flotation concentrates, gravity concentrates, etc. |
| Polished sections. |
| Thin sections. |
| Photomicrographs. |
MSRDI has pilot plant facilities for larger scale tests. The pilot plant is utilized to analyze, determine and assess a process(es) and help determine accurate parameters for flowsheet design and operation; process confirmation and product quality evaluation. A locked-cycle test may sometimes be a more economical alternative.
Pilot plant testing capabilities include:
| Twenty ton per hour portable crusher with screening plant. |
| Fifty foot by seventy foot concrete pad for large cone and quartering, sample blending. |
| Ball mill size thirty inches by thirty inches with a twelve-inch spiral classifier. |
| Autogenous/semi-autogenous mill size two feet by six feet. |
| Three various size regrind mills. |
| Table and jigs. |
| Humphrey spiral. |
| Heavy Media Separation (HMS)-6" Dyna Whirlpool heavy media concentration plant. |
Preconcentration technology, although known for some time, has not been used extensively. With the need to reduce capital and operating costs under existing mining environments, HMS preconcentration as a means of improving economic viability should be considered.
Benefits; Reduction of capital
expenditures by 50-75 %
Reduction of operating costs by 50 %
Lower energy requirements
Lower reagent costs
Lower labor costs
Lower tailings disposal costs
Increase mine production without expansion of milling facilities
Environmentally attractive alternative
Discard
30-70 % of the waste at coarse size ( before grinding )
Use of discarded waste as mine fill
Use of discarded waste as trap rock
Less water requirements and treatment
Applications of HMS technology
Preconcentration of Pb-Zn-Cu-Au-Ag ores
Preconcentration of non-metallic ores
Fluorspar,
Barite, Phosphates, Limestone, Spodumene, etc.
Preconcentration of coal, carbon products, and municipal wastes
Recovery of diamonds, emeralds, rubies, etc.
| SAG mill/ball mill flotation circuit. |
| Flotation banks with various configurations. |
| Thickeners from four foot to eight foot diameters. |
| Agitation leach (mechanical or air). |
| Four, 2' x 9' rubber lined columns for heap leaching. |
| Three-eight inch by twenty-foot columns. |
| Heap leach heights to 25 feet. |
| Single column capacity up to 2.5 tons. |
| Drum agglomerator. |
| Ten-gallon/minute liquid ion exchange pilot plant with electrowinning circuit. MSRDI, in collaboration with LEACHINC, uses modeling software to scale up and project commercial heap leach performance from laboratory column test data. |
|
| Kilns. |
| Crucible and segregation furnaces. |