devico in zinkgruvan, sweden. zinkgruvan mine owned by lundin mining zinc lead, silver, copper...

Devico in Zinkgruvan,Sweden

Zinkgruvan mine

• Owned by Lundin Mining• Zinc• Lead, silver, copper• Greatly folded

mineralization• Ore body varies from

700 to 1200m vertical depth

Previous drilling

• New discovery• Few and spread

boreholes• BQ-TK core drilling

• Effective• High unstable

deviation

Devico in Zinkgruvan

• Contact late 2006• Delineate the new

discovery• Time saving• Accuracy

Devico in Zinkgruvan

• Started in May 2007• Old 56mm borehole, 65° inclination• Reamed to 76mm and sidetracked at 630m• Targets at 900 to 1200m depth

• Second drill rig in August 2007• Old 56mm borehole, 69° inclination• Reamed to 76mm and sidetracked at 330m• Targets at 700 to 1000m depth

Sidetracking

• Initial sidetracks from 56mm to 76mm• DeviDrill• Corac core barrel

• Other sidetracks• Cut out of curve• 2-3 wedges

Cut the curve

Borehole steering

• 100m between targets• 30 - 50m directional drilling initially• Up to 150m total steering to hit one

target

Precision

• 5 or 10m target limits, less in certain directions• At times, 3 corrections in one hole• Corrections down to 1050m depth

Target hit angle

• Sidetracked boreholes gets inclination of 45°-80°

• Sometimes parallel with ore body

Deep inclination changes– 15 degrees and more

– 60m or more

Results

• 12-13 sidetracks• New mother hole under planning• Satisfied geologist!

• “From the beginning people were talking about production gain and cost gain with Devico but this aspect of being able to chase the ore horizon when the geology decides to disobey, gives me as a geologist a much easier job and better health”