NI 43-101 Technical report, Surface diamond drilling ... - Iamgold

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1. Base station data were manually edited for cultural interference.
2. A ‘height correction’ based on IGRF was applied to account for height deviations from drape.
3. IGRF was removed after levelling.
4. Corrugation still remains between ties after tie-line levelling. As a result, two passes of micro-levelling were used. Both passes use a
variable clip to minimize filtering in areas where intersection levelling is effective. In pass 1, the degree of micro-levelling is limited by
altitude deviation from drape, while pass 2 is limited by the relative activity of the block, using the analytic signal of mreslvl. See Table
I below for processing parameters.
5. IGRF is calculated at a fixed average survey height on a fixed date (Table I).
PROCESSING PARAMETERS (Table I):
Block
1 Lepine (L)
2 Bousquet-Odyno
(B)
Grid
Filter
Length
(m)
250
3 Niobec (N) 250
Pass 1 – Deviation
from drape (m)
Clip (nT)
Pass 2 –
Analytic
Signal (nT)
Clip (nT)
10 50 3.0 7
10 25 1.5 25
10 50 3.0 7
IGRF Altitude
(m above MSL)
IGRF Date
342.5 2012/05/04
348.2 2012/05/06
163.0 2012/05/12
GRIDS (TABLE II):
1
2
3
Grid Name
12002_L_TMF.grd
12002_B_TMF.grd
12002_N_TMF.grd
12002_L_RTF.grd
12002_B_RTF.grd
12002_N_RTF.grd
12002_L_FVM.grd
12002_B_FVM.grd
12002_N_FVM.grd
Units Comments
Gridded from mreslvld2 channel (Micro-levelled total field magnetic)
nT WGS-84 UTM17N, (B),(L)
WGS-84 MTM Zone7 (N)
Gridded from mreslvld2i channel (Micro-levelled total field magnetic, IGRF corrected)
nT WGS-84 UTM17N, (B),(L)
WGS-84 MTM Zone7 (N)
First Vertical Derivative of mreslvld2 (Micro-levelled total field magnetic)
nT/m WGS-84 UTM17N, (B),(L)
WGS-84 MTM Zone7 (N)
IAMGOLD Corporation Page 157
Levé magnétique héliporté 15 juillet 2012
Blocs Lepine, Bousquet-Odyno et Niobec EON 12002