Borehole A passes through a coal seam at a depth of 50 m and reaches a lower coal seam at a depth of 450 m. Boreholes B and C reach the lower coal seam at depths of 150 m and 250 m respectively. Assume that the two coal seams are planar and very thin, that is, at the given scale they can be represented by a single line on the map. Also assume that the two coal seams have a constant vertical separation of 400 m.

a) Determine the strike and dip of the lower coal seam.

b) Map the outcrops of both lower and upper coal seams using a 50-m structure contour interval .

c) Colour and label areas where the upper seam is at a depth less than 150 m below the ground surface

 

1100 -1000 700 1 800 1 0 900 800 V SCALE metres 1000 500 Z+ N