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2.2
Machine Crushing: To obtain whole-rock chips
Aim
To obtain fresh, millimetre sized chips of basalt. Use this method if the sample material is going to be
analysed for elemental concentrations.
2.2.1
Procedure
1. Clean down rock crushing room.
Ventilate the room.
Sweep and hoover floor.
Scrub bench surface.
2. Clean the rock crusher.
Take the two jaw plates off of the rock crusher and scrub clean. Use a green scrubbing brush,
run the jaws under the tap once scrubbed, then dry down with paper towel.
Empty and scrub clean the plastic sample collection tray, then dry with paper towel. Leave
overturned on side to dry.
Sweep away all dust from the inside of the jaw crushing machine, paying particular attention
to the gaps between the parts the jaw plates rest on and the surrounding metal, and the tops
of the exterior surfaces just above the jaws.
Replace the jaws, close the machine, and start it running for a few seconds.
Take out the whole sample collection drawer and empty the dust collected in it.
Replace the plastic tray in the drawer and reinsert the drawer beneath the machine, checking
again to see if any dust dislodges itself into the drawer.
3. Start the machine and add the sample, touching it as little as possible.
4. After the grinding has finished, remove the plastic tray and decant the sample into a sample bag.
2.3
Powdering samples
Aim
To obtain a very fine powder of sample material, ready for dissolution for ICP-MS and making disks for
XRF.
Notes
• Frequently wash hands during powdering. Always wash hands between touching different sample
cells and sample bags.
• Never have more than one sample open to the atmosphere at one time, and always close and store
empty agate cells/glass vials away from the work bench.
• Avoid touching the bases of the agate cells, or allowing the cells to come into direct or indirect
contact with sample.
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