A pilot scale laboratory investigation of manual slurry sampling methods
representative of those used in the minerals industry is described.
Samples were taken from slurries made up from silica particles of various
sizes and in various concentrations from a stirred tank and from the
discharge lip of a rectangular launder. Sampling methods from the tank
included immersion flasks and several configurations of a suction probe.
The launder was sampled using a conventional narrow-mouth ladle and
also with a 'mouth organ' stream splitter. Samples were analysed for overall solids concentration and size
distribution and showed different but always significant and often large
biases relative to the known overall composition of the slurry, the nature
and extent of bias being dependent on pulp concentration, particle size,
sampling method and sampling location. Results clearly show the very great difficulty of obtaining
representative samples by simple sampling techniques, although the data
suggest that errors can be reduced by using an appropriately designed and
operated suction probe. Further work will be carried out with the
objective of establishing guidelines for industrial sampling practice.