Forte Analytical has four classifications of testing and services - Metallurgical, Analytical, Geotechnical and Sample Preparation. Each area plays an important role in advancing metal recoveries and heap leach pad performance.
A description of test methods we use include:
PARTICLE SIZE DISTRIBUTION
Cascading shakers/sieves separate ore sizes which are then weighed. Used to determines relative masses of sample size fractions and how that impacts metal extraction. Ore types behave very differently when compacted and leached over time.
A sample and specific combination of fluxes are placed in a high temp furnace to separate the desired contents. (Fluxes are materials that assist with the separate of sample compounds.) Precious metals, Ag, Au, and Pt, fall to the bottom with the lead. The lead is removed from the precious metals by cupellation where a small bead of desired content is isolated. Assay is coupled with a gravimetric or atomic absorption (AA) finish to determine the composition of the bead. Typically more accurate than instrumental analysis, though more time and labor needed.
Fire assay for samples suspected to have coarse deposits. Pulverized samples are screened where the passing and non-passing sample sizes are assayed separately. Results in a significantly more accurate analysis of the Au and Ag components.
MULTI-ELEMENT ICP (Inductively Coupled Plasma), 30 Element Sweep
Three-acid digestion to dissolve the sample into solution before processed with ICP. ICP vaporizes the sample to detect low levels, (ppb), of many elements that can impact leaching and gold encapsulation.
Batches of size specific ore samples are placed in vats with CN solution. Periodically the solution is sampled and analyzed to determine leach rate, recovery and acid consumption.
BOTTLE and COLUMN LEACH
Columns of varying widths are filled with size specific ore samples while a steady flow of leaching solution is applied to the top. The solution is collected at the base and analyzed to determine leach rate, recovery and acid consumption. Most expensive of the leaching tests, but is the most similar to the plant scenario.
WHOLE ROCK XRD
X-ray diffraction analysis of a pulverized ore sample. Identifies fine crystalline structures and overall sample compositions of those structures. Can determine clay and silica contents of a sample which directly impact leaching abilities.
Instrumental analysis mainly used to determine composition of carbons and sulfuric compounds. Organic carbon can rob the sample of its gold content by adsorption, and sulfide can consume the soluble CN-.
Sample is confined to a cylindrical space with a desired load applied. Fluid flows fills into the sample, then is allowed to drain while the drain rate, color and clarity are recorded. These tests give approximations of soil/ore behavior under different heights of heap. (The higher the heap, the higher the pressure, potentially blocking flow.)
Metallurgical flowsheet design
Heap leach design parameters
-Optimal crush size
Crush size to NPV optimization analysis
On-site and off-site lab auditing & training
Sulfur and Iron Oxidizing Microbial Activity
Heterotrophic Microbial Activity
Sulfate-Reducing Microbial Activity
Green Algae Activity
Total Cell Count
Mixed and Pure Culturing
Cells/mL by phase contrast microscopy
Bench scale, pilot scale
DNA extraction, quantification, and 16S Sequencing