Rock preparation

We have an extensive School facility for the preparation of rock samples and other materials in order that they may then be studied using various microscopic and analytical instruments.

The facility includes:

• thin section and rock cutting laboratory
• resin work and impregnation laboratory
• polishing Laboratory
• rock crushing and milling laboratory
• fusion laboratory

Preparations and services that the facility can provide are:

• covered thin sections (26x76mm) for study by transmitted light microscopy
• polished thin sections (28x48mm/76x51mm) for study by light microscopy, scanning electron microscopy and laser work
• polished resin blocks for study by reflected light microscopy, scanning electron microscopy and laser work
• double polished thins for the study of fluid inclusions
• colloidal silica polishing for electron backscatter diffraction (EBSD) analysis
• cutting rocks and specimens of various sizes using diamond blades
• crushing and milling samples to fine powders for inductively coupled plasma (ICP), X-ray fluorescence (XRF) and X-ray diffraction (XRD) analysis
• furnace work for fusion, ashing and loss of ignition for ICP analysis and other analytical methods

Thin section and rock cutting laboratory

The thin section lab allows for production of multiple sections at the same time using lapping jigs on a precision lapping machine.  Sections can then be covered or polished depending on the study required.  Double polished thin wafers can also be produced for the study of fluid inclusions.  A selection of diamond saws enables rocks and other specimens of various sizes to be cut.

Equipment includes:

• Logitech LP50 precision lapping machine
• Logitech GTS1 Thin Section Cut-Off Saw
• Daimond saws with 6” and 10” blades
• Norten CHW Clipper saw

Resin work and impregnation laboratory

Resin blocks, 25mm, 30mm and 40mm of rock samples, gravels, particles, soils and other materials can be produced which can then be polished for study by various analytical techniques.

Friable rocks can also be impregnated with resin using a vacuum system in order to stabilise them for cutting and making into thin sections.

Polishing laboratory

The lab is equipped for the polishing of thin sections, polished blocks, wafer thin rock slices, rock chips and metallurgical samples using aluminium oxide or diamond compounds as the polishing medium.  Colloidal silica is also used to polish samples for EBSD analysis on the scanning electron microscope. The PM5/WG2 polishing system is capable of producing finished samples to a very high standard, whether the requirement is high reflectivity, low relief, or ultra-flat surfaces.

Equipment includes:

• two Logitech PM5 polishing instruments with WG2 power heads
• Stuers DAP-2 Polisher/Grinder
• Buehler Metaserve 250 Polisher/Grinder

Rock crushing and milling laboratory

Rock samples can be crushed and milled to fine powders so that they can be analysed using ICP, XRF and XRD analysis.  A rock splitter or diamond saw can first be used to get the samples down to 5cm square chunks.  A jaw crusher can then crush the samples to approximately 3mm pieces.  A tungsten carbide tema mill or an agate tema or ball mill can then mill the samples to a fine powder.

Equipment includes:

• Fritch Jaw Crusher
• Siebtechnik tungsten carbide tema mill
• Siebtechnik agate tema mill
• Retsch PM400 planetary ball mill

Fusion laboratory

There are a number of ovens and furnaces for drying, ashing and fusing samples. One furnace is used to carry out Loss on Ignitions on rock samples prior to fusion using the Fluxy equipment in the geochemical preparation area.
Equipment includes:

• Two Vecstar chamber furnaces 1100˚C
• Two drying ovens

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