VTEM-ZTEM Airborne EM Survey. Results over PGM-Cu-Ni Targets. at East Bull Lake Anorthositic Complex, Massey, ON

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1 KEGS-PDAC SYMPOSIUM 2011 Meeting Geophysical Challenges: Difficult Environments and Hard to Detect Commodities VTEM-ZTEM Airborne EM Survey Results over PGM-Cu-Ni Targets at East Bull Lake Anorthositic Complex, Massey, ON By Jean M. Legault *, Marta Orta, Harish Kumar and Shengkai Zhao Geotech Ltd., Aurora, ON Presented at KEGS-PDAC Symposium, 5-March-2010, Toronto, ON.

2 KEGS-PDAC SYMPOSIUM 2011 Introduction East Bull Lake Outline Geology and Exploration History Previous Geophysics (MT-AMT Surveys in ) VTEM-ZTEM Description & Features East Bull Lake Airborne EM Results VTEM Results and Interpretation (1.5D CDI + 2.5D Maxwell) ZTEM Results and Interpretation (2D Inversion) Joint VTEM-ZTEM comparison Conclusion

3 East Bull Lake Geology East Bull Lake Intrusion 80km west of Sudbury, near Massey, ON The Paleoproterozoic East Bull Lake Intrusive (EBLI) is one of several layered mafic complexes that occur in a linear belt in Archean Superior Province, along with Agnew and River Valley Huronian Age intrusions. These intrusion all host similar contact-type PGM-Cu-Ni sulphide mineralization. (after Brisbin et al., 2001)

4 EBLI-West East Bull Lake Geology East Bull Lake Geology EBLI-Neck EBLI-East Lower Series Lower Series (Modified after Peck et al. (1995) by Mustang Minerals Corp) East Bull Lake Intrusive is 20 x 4.5 x 1km thick mafic lopolith consisting of two lobes (EBLI-East & EBLI-West) connected by a 3x5km neck and cross-cut by Folson & Parisien Lake Deformation Zones (FLDZ & PLDZ). The EBLI is a gabbro-anorthositic intrusion that is subdivided into 3-4 internal stratigraphies (Upper, Main, Lower and Marginal the contact.) Lower-Marginal Series hosts all known PGE-rich mineralization, related to mainly disseminated sulphides (<1%) but as high as 10% Cu-Po. (after Brisbin et al., 2001)

5 East Bull Lake PGM-Ni-Cu Targets East Bull Lake Geology Mineral exploration at EBLI began with access along logging roads in early 20 TH century mainly focused on Gold and Sulphide prospects. Noranda Mines and other companies investigated base-metals potential in 1950 s and 1960 s PGE potential only recognized in late 1980 s. Extensive study of EBLI mineral potential by Laurentian University and OGS in early 1990 s... Potential for extremely large tonnages of sulphide, even massive sulphides...with PGE enrichment... Late 1990 s, Mustang Minerals leads renewed exploration for bulk, near surface, low grade (e.g., 2.5 g/t Pd+Pt) open pit PGE-Cu-Ni mining. (after Brisbin et al., 2001)

6 Trench at East Bull Lake Sulphides in Parisien Lake Deformation Zone Net Textured Sulphides in DDH core at East Bull Lake Massive Sulphides in DDH core East Bull Lake Exploration Novick Lake VTEM Data Bz dbz/dt TMI In May 2007, Mustang completed a detailed Geotech heliborne VTEM survey over the project and identified previously unknown VTEM anomalies which in several locations are associated with highly anomalous nickel-copper-pgm values in surface samples and drilling. In 2008, initial drilling of first VTEM target (Parisien Lake) intersected 9.3% Cu g/t PGM & 0.4% nickel (

7 Location of Scalar & Tensor AMT-MT Sites at EBLI Average SAMT Soundings East Bull Lake Previous Geophysics 2D Modeling of SAMT Layered Earth 1D Inversions Folson Lake Fault Zone In early 1980 s Atomic Energy of Canada Ltd selects EBLI to test the capability of geotechnical methods for evaluating long-term storage of nuclear waste. In addition to ground VLF EM, magnetic, gravity surveys, both scalar and tensor audio magnetotelluric (AMT-MT) survey data were obtained at EBLI by Geological Survey of Canada, in (Ref. Kurtz et al., 1986) 1k ohm-m Conductive Layer at 800-1km depth Scalar AMT Apparent Resistivity Pseudo-section across FLFZ TE-mode TM-mode FLFZ FLFZ 1D-2D SAMT models indicate: a) Conductive Layer at 0.8-1km depth below EBLI. b) Define major SW dipping conductive structure along Folson Lake FZ. (after Kurtz et al., 1986)

8 Layered Earth 1D Inversions for Tensor AMT-MT Sites East Bull Lake Previous Geophysics Tensor AMT-MT Sounding Curves 1982 Tensor AMT-MT survey and later 83 infill sites confirm scalar AMT survey results, indicating a conductive layer at 800m depth below EBLI. Drilling by AECL in 84 encountered faulted base of EBLI at 770m depth later confirmed by borehole logging. 2D Modeling of Tensor AMT-MT Sounding Profile FLFZ ~2k ohm-m Conductive Layer at 800-1km depth Basal troctolitic layer later found to be PGM bearing. (View Looking SE) (after Kurtz et al., 1986)

9 The VTEM System Parameter VTEM PLUS Base Frequency Waveform Current Peak dipole moment Tx loop diameter (area) Tx number of turns 4 25 Hz/30Hz Trapezoid Survey speed 80 km/h Tx/Rx Clearance 30 m Maximum: 310 A (4.4ms pulse) 200 A (7.5ms) Maximum: Am 2 (4.4ms) Typical: Am 2 (7.5ms) 26 m (540 m 2 ) Tx turn-off time 1.1 ms Tx Pulse On Time Programmable 4.6 to 7.5 ms Rx Time gates Rx coil diameter, m 1.2 (Z) & 0.32 (X) Rx Effective Area, m (Z) & 19.7 (Z) Receiver sampling 0.1sec (approx. 2-3m/sample) Magnetometer Optically pumped caesium vapour Mag Clearance 60 m 2009: 28 ( ms) 2010: 35 ( ms) Mag sensitivity 0.02nT (0.001nT base) Outlining VTEM System Specifications and Key Elements

10 VTEM Technical Highlights The VTEM Transmitter Waveform msec 7.2ms 25/30 Hz base frequency (permits long decay measurements), sampled using up to 50 channels with 2010 acquisition system 26m x 4 turn Transmitter coil (the largest diameter loop available on any airborne geophysical platform), 35m for VTEM Max Large Dipole moment (425,000 Am 2 for VTEM Plus / >900,000 Am 2 for VTEM Max ) with Extremely Low System Noise (< pv/am 4 ) Deep Penetration (arguably best of HTEM systems), typically m for shallow dipping targets, >750m proven (Athabasca Basin, SK). Focused footprint allows to also discriminate smaller targets (i.e., kimberlites, breccia pipes, paleochannels, etc.). Superior Repair or Replace Time (few hours) VTEM X-Z component db/dt & B-field data Concentric Transmitter Receiver geometry ensures accurate anomaly location (response symmetry same regardless of survey direction), Z & X (+/- Y) sensors VTEM is widely considered one of best Helicopter TEM massive sulphide detection & imaging tool; with proven fly-to-drill capability from high accuracy GPS positioning, at 0.1samples/sec. equals 2-3m between data points.

11 The ZTEM System Specifications Parameter ZTEM Transmitter Sampling Frequency A/D = 2000 Hz A/D (0.0005sec) Output = 2.5Hz (0.4s ~10m/sample) Receiver Bird = Hz (Vertical Dipole), Base = Hx-Hy (Horizontal Dipole) Survey speed 80 km/h None required (Passive EM method) Rx Clearance 50 m (nominal) Rx coil diameter Mobile = 7.2m Base = 3.5m Rx Frequencies 32, 45, 90, 180, 360 Hz (+/- 720Hz) or 25, 37, 75, 150, 300 +/- 600Hz Rx Derived Measurements Tx (Hz/Hx) & Ty (Hy/Hz) Tippers (via Tensor FFT) Rx Transfer Functions In-Phase and Quadrature Base Station Receiver Nominal Noise floor <1% Skin Depth Penetration ~1km-3km for 1k Ω-m avg. Host Airborne Receiver ~300m-1km for 100 Ω-m avg. Host Helicopter Magnetometer 90m EM Receiver In ZTEM only Vertical component (Hz) of AFMAG field is measured in receiver coil. The horizontal (Hx-Hy) primary fields are measured at the base-station. This is a distinct advantage in terms of data quality (>10x improvement in S/N over AFMAG).

12 The ZTEM System AFMAG - Background AFMAG stands for Audio Frequency (electro) Magnetics, 1 ST proposed by Ward (1959), redefined by Labson et al (1985). ZTEM ( Z-axis Tipper Electromagnetics) is a variant of AFMAG only Hz receiver is mobile, Hx-Hy sensors at fixed base-station. Passive Electromagnetic (EM) technique in same family as Magnetotellurics (MT), but measuring magnetic fields only - similar to VLF EM but does not use a man-made transmitter, lower frequency, non-periodic signal, 3D measurement. The EM source is the natural field of Earth caused by lightning strikes mainly equatorial thunderstorms and other electrical storms 1000 s of km away create horizontal planar primary fields. Frequency range - audio range Geotech s AFMAG can operate from 22 to 2800 Hz (based on digitizing rate), but in practice we operate from 30 to 360Hz +/- 720Hz (based on signal strength). Basic Principle: Lateral resistivity contrasts cause horizontal EM fields to tilt vertically. Vertical secondary H-field vector called tipper.. The relationship between vertical (Hz) & horizontal (Hx-Hy)-fields is: Hz(f)= Tx (f)*hx(f)+ Ty(f)*Hy(f) Vozoff (1972) Tipper vector (Tx, Ty) determined using FFT processing

13 The ZTEM System ZTEM - Features Excellent sensitivity to lateral resistivity contrasts, for example fault-fracture zones, clay-alteration, silicification, rock permeability/porosity water, etc. but also sensitive to absolute conductivity, such as graphitic shales, massive sulphides, etc Hz frequency Bandwidth provides for deep penetration, makes ZTEM a depth- sounding and profiling tool; mid-low frequency range permits near-4 season survey capability. Superior Exploration Depth (δ S =503* (ρ/f)), easily over 2000 metres in resistive crystalline rocks, less than m in more conductive sedimentary and geothermal settings (30Hz minimum frequency). Relative insensitivity to flight-height variations (due to relatively larger primary field penetration depths, small 1/R 2 fall-off rate) Most importantly, the uniform, plane-wave nature of the natural EM fields permits fast 2D-3D forward & inversion possible on PC Making ZTEM a unique Airborne Geologic Resistivity Mapping Tool. UBC 3D Inversion of ZTEM Data Mt-Milligan Porphyry Copper Deposit (after Oldenburg, Holtham & Shekhtman, PDAC 2009)

14 East Bull Lake AEM Surveys in 07 & 10 Airborne Survey Coverage over EBLI East Block ZTEM not shown at client s request VTEM (2007) lines in red ZTEM (2010) lines in blue 2007 VTEM survey consists of 867 line-km, flown at 100m spaced NS lines and 1km EW tie-lines. dbz/dt and Bz-field TEM and TMI measured ZTEM survey consists of 228 line-km, flown at 200m spaced NW and SE lines (SE not shown by request). Tzx (in-line) & Tzy (cross-line) Tippers and TMI measured, between Hz frequencies.

15 L2180 L2180 H H A number of weak-to-moderately conductive EM anomalies were identified (A-N) occurring either small groups or short lineaments, mostly magnetic. M I L2000 Total Magnetic Intensity M I L2000 VTEM dbz/dt mid-late channel (2307us) Response VTEM Survey Results L1780 L1780

16 L2180 L2180 H H Many VTEM anomalies correlate with known PGM showings, others represent targets for follow-up. PGM showings without VTEM likely represent disseminated sulphides (<1%). M I L2000 2ND Vertical Magnetic Derivative M I L2000 VTEM dbz/dt mid-late channel Time-Constant (Tau) VTEM Survey Results L1780 L1780

17 VTEM Anomaly M at Parisien Lake PGM Zone 0 100m VTEM Interpretation Parisien Lake PGM Occurrence In early 2008 initial drilling of a VTEM target at Parisien Lake yielded intersections that included 1.1m of 9.3% copper and 12/5 g/t PGM from 89m down hole depth and 10m of 0.4% nickel at shallow depth. Maxwell 3D Plate over Parisien Lake (dbz/dt mid-late channel / 2307us)

18 Northern Contact of EBLI Intrusive 30Hz In-Phase DT East Block ZTEM not shown at client s request Several prominent linear conductive trends are identified (ZW1, ZW2) that coincide with Folson Lake FLDZ and northern contact of EBLI. But usually poor correlation with ZTEM and VTEM anomalies, or PGM occurrences. Folson Lake Fault Zone Folson Lake Fault Zone Northern Contact of EBLI Intrusive ZTEM 360Hz In-Phase Total Divergence (DT) ZTEM Survey Results

19 ZTEM Interpretation In-Phase Observed In-Phase Calculated Quadrature Observed Quadrature Calculated TMI and PLM AECL-3 AECL-1,4,2 Southern Contact of EBLI Intrusive Folson Lake Deformation Zone EAST BULL LAKE INTRUSION 770m = Base of EBLI in DDH s (PGM-Mineralized Troctolite) Northern Contact of EBLI Intrusive Masked at Client s Request ZTEM 2D inversions show excellent correlation with major geologic features, as well as location of ddh-tested 770m conductive EBLI base and previous AMT-MT results.

20 ZTEM Interpretation 3D Voxel of 2D ZTEM Inversions over East Bull Lake West EAST BULL LAKE INTRUSION AMT-MT Sites Folson Lake Deformation Zone AECL drillholes PGM-Sulphide Occurrences Northern Contact of EBLI Intrusive Southern Contact of EBLI Intrusive Base of EBLI (Faulted Troctolite) Masked at Client s Request EBLI intrusive is defined as a more resistive body surrounded by lower resistivity rocks at depth, as well as further west and east. These lateral conductors are consistent with Folson Lake FLFZ and the northern EBLI contact, which are known fault-fracture zones. Significantly, ZTEM inversions also define a deep conductive layer at 0.5-1km depth which coincides with the known base of EBLI and agrees with the AMT-MT findings of Kurtz et al. (1986).

21 0 VTEM anomaly I is defined along ZTEM anomaly ZW2, outside EBLI intrusive. However, its ESE trend suggests that VTEM corresponds to sulphide mineralization whereas ZTEM represents NE-trending structural control. VTEM Anomaly I EBLI West ZTEM IP DT North EBLI Contact Base of EBLI ZW2 Anomaly L1020 ZTEM 2D Inversion of Tzx Folson Lake Deformation Zone EAST BULL LAKE INTRUSION VTEM Anomaly I vs. ZTEM ZW2 Masked at Client s Request 100m I VTEM Tau VTEM-ZTEM Comparison L2000

22 Conclusions VTEM survey results from 2007 over the East Bull Lake Intrusive Complex have identified weak to moderate conductance anomalies associated with previously unmapped, highly anomalous PGM-sulphide occurrences, many of which have been successfully drill-tested. ZTEM Tipper AFMAG survey results from 2010 have defined major structures surrounding the EBLI that strikingly agree with previous AMT-MT findings, as well as drilling, including the fractured PGM-mineralized base of the complex, at 800m depths.. The relative success of the VTEM and ZTEM surveys at East Bull Lake is in marked contrast to the apparently poor correlation between VTEM and ZTEM anomalies. This is logically explained by the differences in depth resolution/penetration and relative size-conductivity of the targets that each system is most sensitive to. VTEM is better suited for high resolution mapping of higher-conductance massive to semi-massive sulphide targets in the 0-500m range with depthdetectability/sensitivity proportional to target size.

23 Conclusions - continued On the other hand, ZTEM is better suited for larger scale and deeper resistivity structures, associated with regional geology and sometimes extending to great depth (1-2km), that depend only on lateral resistivity contrasts. It seems that both technologies complement each other as mapping tools of targets of different scale & style as applied to PGM-sulphide exploration. Many existing showing feature well defined VTEM anomalies consistent with massive to semi-massive nickel-copper mineralization, whereas others do not likely due to disseminated sulphide mineralization. On other hand, relatively few ZTEM anomalies correlate with VTEM, inside the EBLI; whereas several coincident VTEM-ZTEM feature occur outside EBLI and point to possible syngenetic, mineralized fault structure or else to MS mineralization unrelated to EBLI in country rocks. Certainly, 3D inversion of ZTEM and VTEM data provide valuable insight and further explanation of the relationship between the mineralized zones and controlling structures at East Bull Lake.

24 KEGS-PDAC SYMPOSIUM 2011 Meeting Geophysical Challenges: Difficult Environments and Hard to Detect Commodities Thank You! Our Thanks to: Presented at KEGS-PDAC Symposium, 5-March-2010, Toronto, ON.