Automated Mineralogy Laboratory

QEMSCANThe Automated Mineralogy Laboratory is a research laboratory within the Center for Subsurface Earth Resources and the Department of Geology and Geological Engineering that is dedicated to mineral characterization and application development for the minerals, energy, environmental, biological, and planetary research groups and industries. The laboratory is equipped with a QEMSCAN®, a revolutionary instrument used for minerals and materials analysis.

The QEMSCAN® method utilizes electron-beam instrument analysis to perform rapid and accurate analysis of mineralogical and industrial samples for research and industry. The focus of the laboratory is to provide improved understanding of materials in order to better predict their management, development, and the effective recovery of resources.

Contact

Department of Geology and Geological Engineering
Colorado School of Mines
1516 Illinois Street
Golden, CO 80401

Dr. Katharina Pfaff
kpfaff@mines.edu
303-384-2487
Fax: 303-273-3859

Applications

Mining and Minerals

Quantitative mineral analysis has a wide variety of applications in the mining and minerals sector. At the Qemscan Facility, research is focused on the identification, quantification and recovery of base metals, precious metals, kimberlites, iron ore, industrial minerals and more.

Mining and Minerals

Energy

With the ever increasing need to explore for and produce energy resources, the Qemscan Facility provides important solutions for oil and gas reservoir characterization. Mineralogy and porosity measurements can be calculated for a variety of rock types including sandstones, fine-grained oil shales, carbonates, coal and more

Energy

Planetary

Planetary

Environment and Biology

Environment and Biology

Geology and Materials

Geology and Materials

Instrumentation

QEMSCANThe QEMSCAN® is a fully automated SEM-based analysis system that provides quantitative mineralogical and textural data on the basis of automated point counting. The instrument contains a custom-built electron-beam platform equipped with four energy dispersive X-ray spectrometers (EDS) for mineral and compound identification within a wide range of sample types.

The iDiscover® software allows for the automated stepping of the electron beam across samples at a user-defined pixel resolution (typically 1 – 40 micrometers). At each pixel, the system collects a backscatter electron (BSE) signal and an EDS spectrum. A mineral or phase identification is made on the basis of the BSE value and elemental intensities.
The QEMSCAN® provides quantitative mineralogical and textural data, false-color mineral maps, and robust statistical data that can be used to quantify a variety of important variables. These include:
  • Highly accurate mineral (phase) abundance (i.e. modal abundance) maps
  • Element X-ray mapping
  • Particle and grain size
  • Particle and grain shape
  • Mineral associations
  • Lithotyping
  • Porosity quantification
  • Organic matter scans
  • Mineral (phase) liberation
The QEMSCAN® is designed to accommodate a diverse array of sample types to optimize scanning ability. These include:
  • Standard thin sections (27 x 46 mm)
  • 30mm and 25mm epoxy mounts
  • Rough rocks and polished rock slabs (Max dimensions: 7.5 x 10 x 2 cm)

Scan Types

The QEMSCAN instrument can perform several different scan types to best suit the needs of each client. Each of these scan types is listed below, and includes a brief description of the primary uses for each type.

  • Field image scans (FI): Produces full false-color images of sample/thin section. Used for imaging of thin sections and whole rock samples. Important uses include:
    • Porosity analyses
    • Organic matter scans
    • Derivation of modal abundances and mineral association data
    • Lithotyping

Organic Scan

Mineralogy Scan

  • QEMSCAN®-based multiple element X-ray mapping
    • Used to produce X-ray maps of specific elements. Please note this scan type can only be used for elements that vary on the level of minor to major concentrations.

X-ray map

  • Particle Mineral Analysis (PMA): Used to scan particles within a particulate sample, this method is used to identify the composition and size of individual particles and to produce a locking and liberation report.

QS Sample

  • Specific Mineral Search (SMS): Similar to PMA, this scan type can be used to search for and identify particles with specific characteristics, such as bright phase minerals within a milling product.
  • Back-scatter intensity + X-ray scans (BSEx): Used to identify bright phase minerals within a whole-rock sample or thin section. This technique, developed at the Qemscan Facility, allows for rapid identification of bright phase minerals such as zircon and monazite, while maintaining the textural context of the minerals through providing a back-scatter image of the material that contains the bright phases of interest.

QEMSCAN Specifications

QEMSCAN® technology is based on the unison of high tech instrumentation and cutting edge software. Analyses are performed with a Carl Zeiss EVO 50 scanning electron microscope (SEM) equipped with four Bruker X275HR silicon drift X-ray detectors. All analysis information is processed using the iMeasure-iDiscover® software suite produced by FEI Inc.

System Features

  • Four Bruker X275HR silicon drift energy dispersive X-ray spectrometers (EDS)
  • Carl Zeiss EVO50 platform
  • One four-quadrant semiconductor diode backscatter electron (BSE) detector
  • One secondary electron detector

Technical Specifications

  • Accelerating voltage: 15kV or 25kV
  • Specimen current – Faraday cup: 5 nA
  • Magnification range: 5x-1,000,000x (default 15x-1000x)
  • Working Distance: 7-50 (default @ 23 mm)
  • Stage Z-distance: 20 mm
  • Energy resolution of 133eV (Mn Ka)
  • 10X10 cm detection area
  • iDiscover software
Sample Preparation

Sample Prep LabIn addition to the instrumentation laboratory, the Qemscan Facility is equipped with a fully operational sample preparation facility. Automated state of the art equipment ensures the efficient and safe preparation of a variety of materials, from dust-sized particles to 10-cm-sized rocks. The Qemscan Facility has both water- and alcohol-based polishing units, allowing us to work with water-soluble compounds as well. The laboratory has the capability for preparing and analyzing a variety of sample types including particulate samples (dust to cm-size), drill core plugs and blocks, thin-section billets, and rough materials up to 10×10 cm in size. In addition, we can analyze polished thin sections. The following sample types can be prepared in our sample preparation facility:

  • Particulate material: These include mill products, sediment samples, and heavy mineral separates
  • Whole-rock material: Samples of nearly any size (max dimensions: 7.5 x 10 x 2 cm) can be cut and polished, or mounted in epoxy for analysis
  • Compounds and alloys: These include industrial materials and metallurgical compounds
  • Carbon tape mounts: Used for mounting coarse-grained material that does not require grinding or polishing prior to analysis
Quality assurance and quality control are the top priorities in sample preparation. From cutting or splitting to mounting, polishing, and coating, high-quality samples are produced during all stages of preparation.

Dry Laboratory Equipment

  • Ductless dust hood for fine-grained sample preparation
  • Rotary Micro Riffler for splitting samples into representative aliquots
  • Hydrosonic bath for sample disaggregation
  • Large oven for sample drying
  • Qake machine for rapid and thorough sample mixing
  • Electronic balance for precise sample measurement
  • Carbon coater for establishing electrical conductivity of each sample
  • Sized fractions of graphite for sample mounting

Wet Equipment

  • Two Struers TegraSystem grinding and polishing stations with diamond polishing grits
  • Struers precision diamond wheel cut-off and grinding machine for specimen preparation
  • Optical microscope and camera to ensure sample quality
  • Molds, resins and hardeners for a variety of sample shapes and sizes
Pricing

The Qemscan Facility uses fixed hourly pricing for scan time on the instrument. Per-hour scanning charges are based on a two-tier structure. Other services, such as sample preparation, are charged at cost.

 Sample Preparation  Price
 Epoxy mounts (30 mm)  $50 per sample
 Polished rock slabs  $150 per sample
 Polished epoxy blocks  $150 per sample
 Carbon coating  $5 per coating cycle
 Scanning Charges  Price
 Research rate*  $75/hr beam time
 Commercial rate  $200/hr beam time
 Other Rates  Price 
 Data reduction and reporting  $75/hr
 Development work**  $75/hr
 Facilities and usage fee***  8.5% of invoice sub-total

*The research rate only applies to academic research projects supported by Mines and accredited universities. Please contact the laboratory to see if your project qualifies for the research rate.

**Development work applies to any time spent in the development of new mineral definitions, new sample preparation techniques, and any new methods of scanning not currently employed in the Qemscan Facility.

***This fee is charged to all non-Mines projects. Research projects endorsed and sponsored by Mines are exempt from this fee.

Publications

Selected publications based on data aquired at the Qemscan Facility:

  • Wunsch, A., Navarre-Stichler, A.K., Moore, J., Ricko, A., McCray, J.E., 2013, Metal release from dolomites at high partial-pressure of CO2. Applied Geochemistry, in press.
  • Nie, J., Peng, W., Pfaff, K., Möller, A. Garzanti, E., Andò, S., Stevens, T., Bird, A., Chang, H., Song, Y., Liu, S., Ji, J., 2013, Controlling factors on heavy mineral assemblages in Chinese loess and Red Clay. Palaeography, Plaeoclimatology, Palaeoecology, 381-382, 110-118.
  • Sharma, R., Prasad, M., Batzle, M., Vega, S., 2013, Sensitivity of flow and elastic properties to fabric heterogeneity in carbonates. Geophysical Prospecting, 61, 270-286.
  • Chin, K., Pearson, D., Ekdale, A.A., 2013, Fossil Worm Burrows Reveal Very Early Terrestrial Animal Actvity and Shed Light on Trophic Resources after the End-Cretaceous Mass Extinction. Plos One, 8, 1-8.
  • Gregory, M.J., Lang, J.R., Gilbert, S., Hoal, K.O., 2013, Geometallurgy of the Pebble Porphyry Copper-Gold-Molybdenum Deposit, Iliamna, Alaska. Economic Geology, 108, 483-494.
  • Lesher, E.K., Honeyman, B.D., Ranville, J.F., 2013, Detection and characterization of uranium-humic complexes during 1D transport studies. Geochimica et Cosmochimica Acta, 109, 127-142.
  • Schmandt, D., Broughton, D., Hitzman, M.W., Plink-Bjorklund, P., Edwards, D., Humphrey, J., 2013, Economic Geology, 108, 1301-1324.
  • Tinnacher, R.M., Nico, P.S., Davis, J.A., Honeyman, B.D., 2013, Effects of Fulvic Acid on Uranium (VI) Sorption Kinetics. Environmental Science & Technology, 47, 6214-6222.
  • Zhao, X.-F., Zhou, M.-F., Hitzman, M.W., Li, J.-W, Bennett, M., Meighan, C., Anderson, E., 2012, Late Paleoproterozoic to Early Mesoproterozoic Tangdan Sedimentary Rock-Hosted Strata-bound Copper Deposit, Yunnan Province, Southwest China. Economic Geology, 107, 357-375.
  • Wandler, A.V., Davis, T.L., Singh, P.K., 2012, An Experimental and Modelig Study on the Response to Varying Pore Pressure and Reservoir Fluids in the Morrow A Sandstone. International Journal of Geophysics, Article ID 726408, 17 pages.
  • Mahan, K.H., Schulte-Pelkum, V., Blackburn, T.J., Bowring, S.A., Dudas, F.O., 2012, Seismic structure and lithospheric rheology from deep crustal xenoliths, central Montana, USA. Geochemistry, Geophysics, Geossystems, 13, 1-11.
  • Barnhart, K.R., Mahan, K., Blackburn, T.J., Bowring, S.A., Dudas, F.O., 2012, Deep crustal xenoliths from central Montana, USA: Implications for the timing and mechanisms of high-velocity lower crust formation. Geosphere, 8, 1408-1428.
  • Ault, A.K., Flowers, R.M., Mahan, K.H., 2012, Quartz shielding of sub-10 um zircons from radiation damage-enhanced Pb loss: An example from a metamorphosed mafic dike, northwestern Wyoming craton. Earth and Planetary Science Letters, 339-340, 57-66.