application of borehole radar to pothole identification and delineation ahead of the working face in...
Post on 16-Dec-2015
216 Views
Preview:
TRANSCRIPT
APPLICATION OF BOREHOLE RADAR TO POTHOLE IDENTIFICATION AND DELINEATION AHEAD OF THE WORKING FACE IN PLATINUM MINES
4th International Platinum Conference: Platinum In Transition ‘Boom or Bust’
11th – 14th October 2010, Sun City, South Africa
SPEAKER:
Charles Golding, CEO, GEOMOLE
AUTHORS:
Carina Kemp, Senior Geophysicist, GEOMOLE
Petro Du Pisani, Manager in-Mine Geophysics, ANGLO TECHNICAL SERVICES
Mduduzi Shoke, Geophysicist, GEOMOLE
Outline
Introduction Efficient
Instrumentation Deployment Methods
Effective Borehole Radar Survey Design Results and Interpretation
Economic Financial Implications
Conclusions
Introduction
Borehole Radar (BHR) provides highly detailed, continuous ore body and structural delineation information for accurate resource definition and mine planning.
Borehole Radar has been delineating ore bodies for mine planning for over 10 years.
Improvements in technology over the last 3 years enable borehole radar to be deployed on the drill allowing for quick and easy surveying underground.
Efficient: Equipment
GeoMole BHR 10 – 124 MHz Bandwidth Resolution: less than1m Range: up to 50m or
more (depending on rock type)
Note: Borehole Radar will not work for all rock types but works very well in the Norites and Anorthosites in the Bushveld.
Probe diameter: 32 mm Length 1.65 m BHR Profiling at ~10
m/min Omni directional antenna
tEfficient: DeploymentThe borehole radar system can be deployed by winch or on the drill rods similar to a gyro survey
Data is acquired continuously as the rods are pulled and the radar ascends the drill holeSignal is sent radially outwards into the surrounding rockThe radar images the rock surrounding the drill hole. The radar is not directional. Neighboring drill holes and knowledge of stratigraphy aids interpretation.
Final interpretation is produced.
Efficient: Forming a radargram
Radargram
Radar deployment
Efficient: Borehole radar process
Radar survey
Geology info
Directional survey Interpretation
Radargram Report & Surface
Database
Thin seam Platinum Mining
BHR for Platinum Mining
Mine Planning: Removing uncertainty - DON’T develop blindly
Geo-technical information prior to development - shaft and raise planning
Mapping the extent and location of dilution zones before mining – knowing what to avoid or investigate further
Extending the life of the mine – greater confidence in resource estimation
Why Borehole Radar?
Tactical Mining ToolRemoving uncertainty - DON’T mine blindly Providing a means to “view” the space that lies
ahead of the working face - mapping the extent of structures and uncertainties ahead of mining
Mapping complex deposits Mapping man-made structures, e.g. old
workings Illuminating sources of physical instability to
allow the miner to either anticipate or even avoid hazards altogether
Safety - locating potentially hazardous zones
Reef thinning <50cm Potholes
Thin seam Platinum Mining
Effective: Thin seam Platinum Mining
HOST ROCKBOREHOLES
RAISE
HAULAGE
CROSS CUT
Effective: BHR Survey Layout
HOST ROCKBOREHOLES
RADAR SURFACE
RAISE
HAULAGE
CROSS CUT
Effective: BHR Surface Generation
Effective: Survey Layout
Effective: Borehole Design
Borehole
± 10m
± 5m
± 25m
± 4m
± 5m
± 7m
Anorthosite
PxA
Feldspathic Pyroxenite
Triplets ~0.3m
Leader Seam ~0.2m
Main Seam (UG2) ~0.7mPegmatoidal Feldspathic Pyroxenite ~0.6m
Mela- to Leuconorite(BLESKOP MARKER)Pegmatoidal Feldspathic Pyroxenite ~0.9mAnorthosite ~0.9m
Leuconorite
8mm Cr. Stringer
Feldspathic Pyroxenite ~4m
UG1 ~0.1 – 1m
Anorthosite
Effective: All Five Radargrams
Effective: Section
Effective: Interpretation
Example
Example: Conclusion
Fortunately no significant disruptions, other than a 2.2m pull down from a reef roll, were detected ahead of mining with the borehole radar for this panel. This meant that mining could continue with confidence.
However…………
DISTANCE FROM COLLAR (m)
UG2 SHEARS & DROPSPULLING PxA ~2M
RADI
AL D
ISTA
NCE
FRO
M B
ORE
HOLE
(m) UG1
BleskopMarker
UG2
PxA
UG2 COLLAPSE INTO~ 15m POTHOLE
UG2 HANGING WALLPxA BREAK-AWAY
Economic: Financial Implications
Borehole radar survey results which were the subject of a different paper (Du Pisani 2008) detected a significant reef roll in a nearby panel. The paper showed that borehole radar surveys ahead of mining could have saved over US$1M in unnecessary development in panels that contain un-mineable reef.
Economic: Financial Implications
Item Extent Tonnes Cost
Avoidable mining
4300m2 14,400 US$ 1.03m
Avoidable development
338m US$ 0.23m
Total US$1.26m
Financial impact summarised (after Du Pisani, 2008)
Economic: Financial ImplicationsImpact of reduced dilution: An average mine mines (say) 2 million tonnes per
annum Assume on-mine costs of approximately US$62.8
per tonne; 2 million tonnes will therefore cost US$125.7m
Geological losses ranges from 5% to 30% Every 1% reduction in waste mined will save
US$1.26m. 5% - US$6.29 This is only the on-mine cost saving. There are
significant additional costs incurred in processing waste.
Economic: Financial ImplicationsImpact of reduced dilution (continued):
A 50 hole a year Self-Drive BHR program will cost:
A 1% reduction in waste because of geological certainty will pay for BHR!
Borehole radar costs $ 186,000
Drilling costs at R600 per metre for 50 x 200metre holes
$ 857,000
Additional staff/consultants $ 100,000
Total borehole radar costs per annum $ 1,143,000
Advantages of using BHR in Platinum Intelligent development Reduced dilution Additional ore More confidence in resource estimation –
continuous ore body maps Safety improvement; AND It is inexpensive and easy to use
Conclusions
Borehole radar technology has come of age and provides a demonstrably efficient, effective and economic means of mining smarter.
Supply side constraints facing the platinum industry will be mitigated by being more efficient, BHR can help.
Successful implementation requires: mine management to see BHR as an operational tool;
and a strong partnership between the supplier and the end
user.
Acknowledgements
The authors thank: Anglo Platinum for allowing these results to be published
and for their vision and support of the implementation of geophysical programs.
all the Rustenburg geologists, borehole radar surveyors and drilling contractor Rosond who have made these borehole radar surveys possible.
the mine staff of Anglo Platinum for their professional enthusiasm which made this study both possible and enjoyable.
The authors gratefully acknowledge the scientific and technical
contributions of the borehole radar research teams at: The University of Sydney The University of Stellenbosch CRCMining
top related