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Synthetic Model Testing and Titan-24 DC Resistivity Results at Wheeler River

Synthetic Model Testing and Titan-24 DC Resistivity Results at Wheeler River. An Athabasca-type Unconformity Uranium Target in Northwestern Saskatchewan, Canada.

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Synthetic Model Testing and Titan-24 DC Resistivity Results at Wheeler River

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  1. Synthetic Model Testing and Titan-24 DC Resistivity Results at Wheeler River An Athabasca-type Unconformity Uranium Target in Northwestern Saskatchewan, Canada By: Jean M. Legault*, Quantec Geoscience Ltd., Toronto, ON Don Carriere, Carriere Process Management Ltd., Mississauga, ON Larry Petrie, Denison Mines Corporation, Saskatoon, SK

  2. Wheeler River Case History • Survey design based on initial synthetic model testing (best approach) • Comparison of several array configurations(modeling and field application) • Presence of major powerline impacts geophysics(choice of methods) • Compare 2-D and 3-D Inversion results(improve understanding)

  3. Titan 24 DCIP & MT Overview

  4. Titan PldpdpCombinesPldp-left + Pldp-right Common DCIP Electrode Arrays

  5. N=0.5 Line Length approx. 4.4 kmCurrent Injections inside& outside Rx Array N=10.5 Extended Titan spread(adding current extensionsbeyond end of receiver array) N=0.5-33.5, a=100m(approx. 1032 points) N=23.5 N=33.5 TITAN DCIP ARRAY CONFIGURATIONS Titan-24 Pole-Dipole-Dipole Pseudosections N=0.5 Line Length 2.4 kmCurrent Injectionsinside Rx Array Standard Titan spread N=0.5 to 23.5, a= 100m(552 data points) Note: Combinespldp & dppl data N=23.5 Note: Combinespldp & dppl data

  6. Case History: M-zone at Wheeler River Commissioned by Denison Mines Corporationin JV with Cameco Corporationand Japan-Canada Uranium Ltd. April-May, 2007

  7. Titan Survey Objectives • Wheeler River mineralization occurs in 400m thick Athabasca Sandstone along the Unconformity, below alteration zone that is associated with underlying basement Graphitic metapelites known as the M-Zone conductive trend. • Define DC (+/- IP) signatures associated with:a) Uranium-bearing graphitic conductor at M-Zone • b) Granitic gneiss to the south-east of M-Zone • c) Alteration chimney in sandstones above M-Zone • Test Titan multi-parameter capability, with emphasis onGalvanic DC Resistivity (possibly also IP) using Pole-Dipole Array, in direct comparison with Dipole-Dipole and more widely used Pole-Pole Array. • Field Surveys were preceded by 2-D synthetic modeling study that tested for optimal array parameters (dipole size) and configurations (Pldp vs Plpl vs Dpdp array).

  8. Wheeler River Project Introduction HISTORIC NOTES • 35km NE of Key Lake & 10km W of Moore Lake. WheelerRiverLocation: • Originally discovered in 1980’s (UTEM follow-up of Airborne) but remained unexplored until recently. Moore Lake Key Lake • Since 1980’s, major powerline through property (along BL) – impacts EM follow-up.

  9. ALTERATION ASSOCIATED WITH UNCONFORMITY-HOSTED URANIUM DEPOSITS • Possible Targets: • Alteration Zone • Unconformity • Basement Graphite Silicification Clay-Alteration BASEMENT AND UNCONFORMITY HOSTED URANIUM DEPOSIT STYLES • Mineralization occurs: a) at unconformity,b) above graphite, c) with basement elevation change. M-ZoneDepositStyle:

  10. Pelitic Metasedimentsin Basement Granitic Gneissin Basement Drillholes L100S M-ZONE M-ZONE L100S WHEELER M-ZONE – AIRBORNE TOTAL FIELD MAGNETICS Powerline Road 0 200m

  11. WHEELER M-ZONE – GEOLOGIC SECTION ACROSS L100S BL 0E M-ZONE DRILLING 0 200m Plan View L 100S 380-400m UraniumMineralizedZone VR-205 ZM-06 ZM-11 ZM-10 - Ground Surface Overburden (<10m) -> Manitou Falls D ->(10-20m thick) GEOLOGIC NOTES Manitou Falls C -> Sandstone(80-90m thick) • Known Geology is based on drilling Along a Narrow Corridor, with Little Known Outside that line. Manitou Falls B -> Sandstone(100-120m thick) • Basement Dips Uncertain – possibly Steep Southeast • M-zone consists of DDH Intersections along Graphitic Conductor and Elevation Change in Basement Topography. Manitou Falls A -> Sandstone(70-100m thick) - Unconformity Basement Rocks -> Arkose-Anatexite (blues) Pegmatite-Granite (pink)Pelite-Graphites (grey-black) 0 50m View Looking NE

  12. Case History: Wheeler River 2-D Synthetic Modeling

  13. Water 100 – 2 000  m Overburden 10 - 100 k  m Lake seds 100 - 500  m Sandstone 2 000 – 5 000  m Contact Alteration 50 -20 000  m Fault UC Unconformity Psammitic (Felsic) Gneiss 5 - 100 k m Granite 10 - 100 k m Graphitic Metapelite <1 -50  m Metapelite 50 -1 000  m (from Witherly, 2005) GEOPHYSICAL PROPERTY MODEL for ATHABASCA-TYPE URANIUM DEPOSITS

  14. 10-10k ohm-metres UBC 2d Synthetic Forward Model Data Note: 500m (n=10)Current extensions 50m A-spacing 0 500m A) Extended Titan Pole-dipole Array a=50m / n=0.5-33.5 3000 ohm-m 300m - 2d Reference Model 100m Note: Gp response onlyat base of pseudosection, i.e.,50m a-spacing likely providesinsufficient penetration 5 ohm-m 1000 ohm-m 1000m - 2.2 km Total array length 3000 ohm-m 10-10k ohm-metres Note: 600m (n=6)Current extensions UBC 2d SyntheticForward Model Data B) Extended Titan Pole-dipole Array a=100m / n=0.5-29.5 0 500m 2d Reference Model 100m A-spacing Note: Gp response in middle,i.e., 100m a-spacing likely providessufficient penetration and focuswithin Sandstone and Gp 3000 ohm-m 300m - 100m 1000 ohm-m 5 ohm-m 1000m - 3.7 km Total array length 10-10kohm-metres Note: 1500m (n=10)Current extensions UBC 2d SyntheticForward Model Data C) Extended Titan Pole-dipole Array a=150m / n=0.5-33.5 150m A-spacing 0 500m Note: Gp response in upper 1/3,i.e., 150m a-spacing possiblyexceeds required penetrationlacks and focus within Sandstone 3000 ohm-m 300m - 2d Reference Model 100m 1000 ohm-m 5 ohm-m 6.75 km Total array length 1000m - Titan Multi-Array DC Survey 2D DC Forward Models

  15. Multi-Array Survey 2D Synthetic DC Inversions A) Range 10 to 10kohm-metres 0m - 2d DC ResistivityDipole-dipole Array -300m Unconformity 500m - Note: Dpdp provideshigh resolution but possibly lacks depth penetration 1000m - B) Range 10k to 10ohm-metres 0m - 2d DC ResistivityPole-dipole Array • -300m Unconformity 500m - Note: Pldp providesgood balance between resolution and depth penetration 1000m - C) Range 10 to 10kohm-metres 0m - 2d DC ResistivityPole-pole Array • -300mUnconformity 500m - Note: Pldp providesbest depth penetrationbut possibly lacks deep resolution 1000m - 0 500m 1500m - Loke 2d Inversions using Res2dInv (Loke and Barker, 1996)

  16. Case History: Wheeler River DC/IP Field Tests along L100S

  17. ROAD L100S M-ZONE M-ZONE POWERLINE L100S 0 1km

  18. IP Phase Pseudosections(Max 3mrad error shown) Apparent Resistivity Pseudosections(Max 10% Vp error shown) Range 0 to 30 milliradians ? ? Range 10 to 10kohm-metres Note: Weaker DC Lowand No IP high over GP - N=17.5 431 of 1091 total pts(40%) retained for Inversion 887 of 1091 total pts(81%) retained for Inversion N=28.5 - Dipole-dipole Array Dipole-dipole Array (a=100m / n=0.5-17.5 / 0.55A avg) (a=100m / n=0.5-28.5 / 0.55A avg) Range 0 to 30 milliradians Range 10 to 10kohm-metres Note: Coincident DCLow + IP High over Gp - N=19.5 785 of 1166 total pts(68%) retained for Inversion 1160 of 1166 total pts(>99%) retained for Inversion N=33.5 - Pole-dipole Array Pole-dipole Array (a=100m / n=0.5-33.5 / 0.51A avg) (a=100m / n=0.5-19.5 / 0.51A avg) Range 0 to 30 milliradians Range 10 to 10k ohm-metres Note: Strong but Wide DC Low + No IP high over GP - N=17.5 571 of 1150 total pts (50%) retained for Inversion 1089 of 1150 total pts(95%) retained for Inversion N=27.5 - Pole-pole Array Pole-Pole Array 0 500m (a=100m / n=0.5-27.5 / 0.73A avg) (a=100m / n=0.5-17.5 / 0.73A avg) Line 100S Titan DC Survey 2D DC/IP Pseudosections

  19. A) Range 10 to 10kohm-metres 0m - -400m Unconformity 2d DC ResistivityDipole-dipole Array 500m - Note: Dpdp provides high resolution but lacks depth penetration 1000m - B) Range 10k to 10ohm-metres 0m - 2d DC ResistivityPole-dipole Array • -400m Unconformity 500m - Note: Pldp provides best balance between resolution and penetration 1000m - C) Range 10 to 10kohm-metres 0m - 2d DC ResistivityPole-pole Array • -400m Unconformity 500m - Note: Plpl provides most depth penetration but possibly lacks resolution 1000m - 0 500m Loke 2d Inversions using Res2dInv (Loke and Barker, 1996) Line 100S Titan DC Survey 2D DC Inversions

  20. Line 100S DC, IP & MT2D & 3D Inversions Range 10 to 10kohm-metres 0m - -400m Unconformity 0m - 2d DC Resistivity 500m - Alteration Zone Granite Contact? Graphite Note: 2d DC suggests W-dipfor M-zone 500m - 1000m - Granite Contact? Graphite Loke 2d Inversions using Res2dInv (Loke and Barker, 1996a) 1000m - Loke 3d Inversions using Res2dInv (Loke and Barker, 1996b) Range 0 to 50milliradians 0m - Alteration Zone? • -400m Unconformity 0m - 2d IP Chargeability 500m - Alteration Zone? Note: M-zone poorly resolved Graphite? Granite Contact? 500m - 1000m - Graphite Granite Contact? Loke 2d Inversions using Res2dInv (Loke and Barker, 1996a) 1000m - Loke 3d Inversions using Res2dInv (Loke and Barker, 1996b) Range 10 to 10kohm-metres 0m - Alteration Zone 2d PW MT TM-TE Resistivity • -400m Unconformity 500m - Note: M-zone alteration appears well resolved but conductor dip andcontrast differs w DC Graphite 1000m - Granite-Metasediment Contact? 1500m - Quantec PW2dia Inversions based on algorithm by de Lugao and Wannamaker (1996) Alteration Zone 3d DC Resistivity Note: 3d DC indicates steeper dip 3d IP Chargeability Note: 3d IP resolves M-zone 0 500m

  21. A) Z=20m Z=1250m Z=1200m Z=1150m Z=1100m Z=1050m Z=1000m Z=1300m Z=450m Z=250m Z=200m Z=150m Z=300m Z=350m Z=100m Z=600m Z=500m Z=550m Z=650m Z=700m Z=400m Z=850m Z=950m Z=900m Z=800m Z=750m Z=50m Note: Migration of GraphiteConductive Zone to NW Note: Powerline Visiblein Near Surface Note: Alteration Visible100m above UC Note: Graphite Visiblein Basement WHEELER M-ZONE – 3-D VOLUME of 2-D SMOOTH DC RESISTIVITY

  22. Z=700m Z=1400m Z=500m Z=900m Z=100m Z=20m Z=300m Z=1100m Note: PL+Road+NoiseVisible in Near Surface Note: Alteration in IP low above UC? Note: Graphite IP High? Note: Graphite IP High? Note: Graphite IP High? Note: Graphite IP High? WHEELER M-ZONE – 3-D VOLUME of 2-D SMOOTH CHARGEABILITY

  23. Z=500m Z=1400m Z=100m Z=300m Z=20m Z=1300m Z=900m Note: Graphite wellresolved in basement Note: Absence of NWmigration in Gp signature Note: Absence of NWmigration in Gp signature Note focused DC resistivitylow 100m above UC Note: Powerline correlateswith near surface DC low WHEELER M-ZONE – 3-D VOLUME of 3-D SMOOTH RESISTIVITY

  24. Z=1400m Z=200m Z=900m Z=1300m Z=500m Z=100m Z=300m Note: Well definedIP high along DC low(except on north lines) Note: Well definedIP high along DC low(also on north lines) Note: Well definedIP high along DC low(also on north lines) Note widespreadpresence of IP highlayer in sandstone Note: Layer-like IP-High zone in sandstone? WHEELER M-ZONE – 3-D VOLUME of 3-D SMOOTH CHARGEABILITY

  25. Study Findings • Field surveys corroborated our initial 2-D DC synthetic modeling studies, i.e., Dpdp offered best resolution but poorest penetration; Plpl had greatest penetration but poorer resolution; Pldp had better combination of resolution, penetration and economy. • DC resistivity data quality and survey productivity greatly improved current injections (>0.5A avg), thanks to more powerful GDD Tx – suggests >2-3 season capability for DC/IP. • DC resistivity results do not appear to be significantly hindered by powerline effects, but IP significantly more affected (acceptable). • MT data quality excellent – not hindered by ground contacts or Powerline effects – confirms all season capability. • Multi-parameter DC-IP-MT results show remarkable similarities and contrasting behaviour (i.e., DC vs MT; 2D vs 3D). • 3-D inversions simplify, improve understanding of responses. • Coincident DC+MT resistivity low and IP high confirmed over graphite > additional tool for geologic mapping & discrimination.

  26. Titan-24 DC Resistivity Results at Wheeler River Thank You DENISON MINES Corporation Toronto, ON Japan-Canada Uranium Tokyo, Japan CAMECO Corporation Saskatoon, SK Toronto, ON

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