UPDATE ON THE

DEVELOPMENT OF A BOREHOLE GRAVIMETER FOR MINING

APPLICATIONS

SEIGEL, CHOUTEAU, GIROUX & NIND

Applications of BH Gravity in Mining

Remote Detection• Massive Sulphide Deposits• Other Types of Metallic Deposits• Non-Metallic Deposits• Verification of Surface and Airborne Gravity Anomalies

Bulk Density Determinations and Applications to Mining• Deposit evaluation• Improved grade control• Relative local rock strength• Monitoring integrity of dams and tailings ponds

REMOTE DETECTIONKelly Lake: Near Miss

BULK DENSITY

PNNL Waste Treatment Plant,

Hanford, WA

ρ = g’/(4πG) = 0.01193 g’

“Gravilog”BHG for Mining

TARGET SPECIFICATIONSensitivity < 5 uGal with 1 minute reading time

Operating range 7000 mGal

Sonde diameter < 48 mm

Sonde length < 2 m

Operating depth < 2000 m (water filled hole)

Hole diameter NQ drill rods (57.2 mm)

Deviation off vertical < 60 degrees

Operating temperature 0C to +70C (downhole section)

Positioning in BH +/- 5 cm (vertical), relative, between stations

GRAVILOG Development

• Three year development & testing• Funding:

– Industry (CAMIRO)• CVRD Inco, BHPB, Areva & Schlumberger

– Canadian Government (IRAP)– Scintrex

• Work Plan– Product development at Scintrex– Modelling software at École Polytechnique

• Start: Oct 2005• Field Tests in Boreholes: mid 2008

GRAVILOG Design Layout

GRAVILOG Sensor Housing

GRAVILOG User Interface

GRAVILOG Modeling Software

GRAVILOGSystem Test Program

BENCH TESTS• Individual components tested prior to assembly• Complete prototype systemSHAKE – DOWN TESTS• Borehole near Lindsay (Sir Sanford Fleming)

– Proper functioning of all Gravilog modules & sensors– S.D of one minute measurements– Repeatability– Debugging– Efficient logging procedures

OPERATIONAL TESTS IN SPONSORS’ BOREHOLES

GRAVILOGBHG for Mining Applications

• Development nearing completion

• Modeling software complete

• Industry sponsors’ boreholes: mid 2008

• Production logging system: January 2009

CREDITS

• CAMIRO – Tom Lane

• CVRD Inco – Alan King

• BHP Billiton – Peter Diorio

• Areva – Grant Nimeck & Rod Koch

• Schlumberger – Harold Pfutzner

• IRAP – Ramesh Gupta

• Sir Sanford Fleming College