Open Collections

Variability of samples from various drilling and sampling methods

Tailings and Mine Waste Conference (2015 : Vancouver, B.C.); University of British Columbia. Norman B. Keevil Institute of Mining Engineering

A series of supplementary geotechnical investigations were conducted at the Questa Mine Site in 2013 and 2014 to collect additional information regarding the waste rock piles located on the site. These investigations highlighted the effects that different drilling and sampling methods can have on soil samples and the associated geotechnical laboratory characterization testing. Samples were collected from a series of collocated Becker borings and test pits and particle size distributions were determined for the samples collected from the two different investigation and sampling methods. The Becker samples had 3 percent more material passing the number 200 sieve and 11 percent more material passing the number 4 sieve than the test pit samples. Additionally two sets of Becker and sonic companion holes were drilled through the waste rock piles, with the Becker samples taken from a split spoon sampler and the sonic samples taken from the sonic core. The average fines content of the sonic core was found to be similar to that of the samples taken from the Becker split spoon sampler. However, the sonic drilling method resulted in significant zones of drill induced breakage and creation of rock flour in zones of dry gravel and/or cobbles within the rock pile. These drill induced breakage zones resulted in core with much higher fines content than the corresponding zones sampled from the Becker drilling. An analysis of shear strength test results on many Questa rock pile samples showed a relationship of decreasing friction angle with an increase in the percentage of fines. The higher fines contents of the Becker and sonic samples versus test pit or in situ samples needs to be considered when selecting appropriate shear strength parameters based on laboratory testing.

Conference Paper

eng

Vancouver : University of British Columbia Library

10.14288/1.0314308

Applied Science, Faculty of; Mining Engineering, Keevil Institute of

Other

DSpace