GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 3.3 707 to 117-210 m and the magnetite ores are occurred in the bedrocks. The top buried-depth of orebodies is average 200 m and orebodies incline to south-west direction average 70°. For example, ZK21201 drilled an magnetite ore belt with apparent thickness 169.23 m (i.e., from 189.61 m to 358.84 m depth). Based on other drillholes ZK21202, ZK21203 and ZK21204, it is inferred that the magnetite orebodies dip to south-west direction around 70° and extending length is nearly 300 m. The southern targeted magnetic source is reconstructed to be buried at 300-350 m depth. This is a concealed and potential iron orebody which has not been verified by drillings. But the size of the orebody is speculated to be smaller than northern ore belts. Subsequently, the correlation coefficient method (M-IDC) and iteration method (M-IDI) are used to determine the magnetization direction. The magnetization inclination and declination are bound constrained as: 0° ≤ I ≤ 90°, 0° ≤ D ≤ 90°. The inclination and declination are varied from 0-90° with a step 1° when calculating the total field anomalies. The correlation coefficients at A ( I = 71°, D = 70°) reach to peak of maximum with R = 0.96907. The estimated optimal inclination and declination using M-IDC method are I = 71°, D = 70° (Fig. 3b). The iterations using M-IDI method finally are convergent to I = 68.4°, D = 70.77° after 5 times of iterations Fig. 2 - a) Total field anomaly and b) frequency-domain transformed magnitude magnetic anomaly of the Galinge iron-ore deposit, NW China. Black points and white-filled polygons show the drillholes and outcropped orebodies in bedrocks, respectively. Fig. 3 - Computed magnetization: a) intensity and b) direction using M-IDC and M-IDI methods of the Galinge iron- ore deposit, NW China.