Upload
markm0705
View
236
Download
2
Tags:
Embed Size (px)
DESCRIPTION
Presentation to Sampling 2010 Perth WA. Experments with blast hole sampling for flitch mining at Mesa A.
Citation preview
Blasthole Cone Sampling Experiments for Iron Ore Flitch Mining
by
Gareth McArthur, Craig Jones and Mark Murphy
Sampling 2010
Thanks to :
Rio TintoGareth McArthur and Craig JonesMine teams at Mesa A and Mesa K
Acknowledgements
Blasthole?Blasthole cone?Flitch mining?
Definitions
What is a blasthole?
What is a blasthole cone?
http://www.youtube.com/watch?v=X3-tbT-_k2Y
What is flitch mining ?
BackgroundGeology
Mesa A
Mesa A/Warramboo
www.epa.wa.gov.au/docs/2566_Bull1264_170907.pdf
Mesa A -simplified geology
Mesa A – geology in mine portal
Mesa A – geology - annotated
Assumptions for flitch miningMethods of sampling
Blasthole cone sampling
Blasthole cone: the 2 : 2: 1 assumption
2 (40%)
2 (40%)
2 (20%)
Blasthole cone: Sampling method
1. Identify two high points2. Cut to slots, A and B3. Sample increments from
faces using the 2:2:1 rule4. Reject the sub drill
increment5. Combine the respective
flitch increments from the A and B slots into the final samples
ProcessHole depth versus sampling face cone heightVariation in cones heights/shapesPainting the cones to mark sampling intervals
Sampling experiments
Sampling experiments1. Test the blasthole rig at Mesa J destined for
Mesa A2. Track the actual depths drilled sampling
interfaces3. Paint the cone at the sampling interfaces4. Collect samples using the 2:2:1 rule on cone
face5. Measure actual sampling interfaces heights
using paint6. Collect second samples using reference paint
marks7. Compare the results
Blasthole depth versus cone height
Cone heights/shapes varies
Painting the cones – white or pink?
Sampling faces – paint lines
Depths to sampling boundariesSampling intervals in cone facesComparison of blind (2:2:1) to painted
sampling intervals
Sampling experiments - results
Depths to sampling boundaries 126 holes
Plot shows the drill rod measurements of end of flitch – driller estimation error
Layer proportion in blasthole cone 126 holes
2:2:1 samples/paint delimited upper flitch
Fe LOI SiO2 Al2O3 P
Mn
TiO2 CaO MgO S
2:2:1 samples/paint delimited, lower flitch
Fe LOI SiO2 Al2O3 P
Mn TiO2 CaO MgO S
Conclusions
Ratio of material report to blast cone is highly variable
Sub-drill is often over represented in the cone by a small fraction
Flitch samples in the cone are on average equal proportions but with high variation from hole to hole
Despite noise and difference between paint-marked actual and 2:2:1 estimated sample intervals grades are similar (albeit noisy) when compared.
Paint markings of boundaries should improve precision.
Conclusions
More detail in AusIMM Publication SAMPLING CONFERENCE / PERTH, WA, 11 - 12 MAY 2010, p 131 to136.