Consulting economic geologist
Jeffrey C. Reid, PhD, PG, CPG

Industrial minerals - services


Petrographic and sterozoom binocular study of diverse industrial minerals and their deposits. Process mineralogy and liberation studies. Example commodities have included: garnet, frac sand, heavy mineral sands (zircon, rutile, ilmenite, monazite), tungsten (scheelite and wolframite tailing studies), scheelite and high-alumina refractory minerals. Some studies have required mineral chemistry as an extension to more routine studies. Some examples are included to the right.

Meet ASTM standard for qualification of petrographers.

Use a transmitted and reflected light petrographic microscope and stereozoom binocular microscope. Fully equipped facility.

Identify the rock type. Describe and document mineralogy, alteration / weathering, deleterious minerals (e.g., iron oxide), unstable minerals (such as expanding clays), grain shape and ratios (including statistical analysis of grain length and width), accessory minerals that could degrade concentrate quality or that could be by-product or co-product minerals, mechanical strength and integrity of grains, and mineral chemistry.

Liberation studies are comprehensive and use crushed and ASTM E-11 specifications for 6-10 mesh size fractions depending on the deposit. Beginning from the most coarse mesh fraction, each size fraction is examined using a stereozoom binocular microscope to determine the "liberation point" for the potentially economic mineral. In addition, visual mineral percent estimates are made for up to 10 sub-samples in each mesh size fraction.

Reports are profusely illustrated in color. Clients are encouraged to review report results in draft form to ensure the report's clarity and meets the client's specifications. After review comments are addressed and the report is finalized, only then is the client invoiced. Reports are in digital formation (PDF) and all residual materials, thin sections, scanned lab notes, and other data are returned to the client in digital format.

Access to x-ray diffraction (XRD), scanning electron microscopes (SEM) and other advanced analytical instruments.

By arrangement, "data mining" including comprehensive database searches to assist exploration programs or corporate strategy planning, core logging, and site studies including investigations of cause of decreased commodity quality.

Tailings studies (mineralogy, size fractions, and chemistry).

Contact us about special problems not listed. We may be able help. Email: Dr. Reid, voice: 919.618.0810.


Above: Garnet liberated from metamorphosed eclogite. Garnet mineral composition was obtained from 'data mining'.

frac sand

Above: Quartz sand from a midwestern location evaluated as a frac sand. Plastic Phi scale to the left. The sand is bimodal and moderately well rounded. Many grains are frosted.


Above: Minus 200 mesh fraction from a tailing pile study viewed with a petrographic microscope. The fraction contains scheelite (SCH), quartz (QTZ), diopside (DIOP), garnet (GT), molybdenite (MOB), and pyrite (PY). The molybdenite and pyrite (both opaque minerals) were identified both in transmitted and reflected light as well by using a stereozoom binocular microscope examining individual mesh sizes. The width of field of view is about 2.9 mm; magnification is 40x. Grain mount in oil, transmitted plane polarized light.

scheelite - probe

Above: Scheelite grain showing strong compositional mineral chemistry zoning as revealed by microprobe study. Microprobe analyses document that the scheelite cores contain more molybdenum than the whiter rims. Complex mineral grain chemistry is revealed by the zoning.. Microprobe instrument conditions shown along with micron scale. Knowing the amount of molybdenum can reveal potential significant trade penalties in concentrate sales. Reflected light study of polished thin section suggested the presence of molybdenite but could not resolve the fine detail shown above. Black dots accompanied by a letter are individual microprobe analytical points. Elemental standards were used in the microprobe study.


Above: Coarse-grained kyanite is fully liberated in this 20x30 mesh interval. The quality is exceptional with no inclusions and only minute inclusions. Garnet is a minor accessory mineral. Typical liberation studies are conducted on material passing nine mesh sizes to: a) determine the mesh size where the mineral of interest is fully liberated, 2) determine and analyze statistically the length and with of grains for each mesh size fraction, and 3) an estimate of the mineral percent of constituent grains for each size fraction. These data help with exploration evaluation as well as with mining and mineral processing flow charts and can help to identify problem areas if they occur. Stereozoom binocular examination of size fractions. The width of field of view is about 5.1 mm.


Above: Zircon from a heavy mineral concentrate - Virginia, USA. The zircon grains are fairly well rounded and sorted reflecting their origin along a paleo-rocky coast. The width of field of view is about 5.1 mm.

heavy minerals rutile

Above: Heavy mineral suite consisting of rutile, ilmenite and zircon - Virginia, USA. The mineral grains are fairly well rounded and sorted reflecting their origin along a paleo-rocky coast. The width of field of view is about 5.1 mm.


Above: Coarse gold - Rio Grande do Norte, Brazil.The gold occurs in shallow placers adjacent to a garnet-quartz rock. The present climate is dry and this is thought to be primary gold, and not remoblized gold in the shallow sub-surface. The width of field of view is about 5.1 mm.


Above: Wolframite slab (left) showing vein structure, sink (s.g. > 2.9) product in plane light (40x, field of view is 2.9 mm) showing the wolframite (opaque), along with fluorite (low relief, nearly translucent with cubic grain sides) in transmitted plane polarized light, and (right) the same view as center image but in cross-polarized light confirming the cubic fluorite. These sink float samples are from a wolframite tailings pile, the slab is from the prospect's abandoned primary crusher site. The wolframite in the slab is the wedge-shaped crystals especially prominent in the lower left side of the slab.

monazite heavy minerals

Above: Monazite, garnet, magnetite, and kyanite in a 50x70 mesh sink (S.G. > 2.9) fraction from a panned concentrate - Piedmont, USA. The width of field of view is about 5.1 mm.