(a) On a contour map A and B are two points whose altitudes are 105m and 95m respectively.
On the map B is located 90m south-east of A. A skew hore-hole at A is drilled in a
south-westerly direction in plan and has an actual inclination of 50° to the horizontal plane.
lt reveals the top and bottom surfaces of a stratum at distances of 50m and 90m,
respectively, from A.
A skew bore-hole at B is drilled in a north-westerly direction in plan and has an actual
inclination of 60° to the horizontal plane. It reveals the top and bottom surfaces of the
stratum at distances of 20m and 100m, respectively, from B.
Determine the dip, strike and thickness of the stratum.
(b) On a seperate contour map R and S are two points whose altitudes are 115m and 100m
respectively. On the map S is located 90m north-east of R. A skew bore-hole at R is
drilled in a northerly direction in plan and has an actual inclination of 55° to the horizontal
plane. It reveals the top and bottom surtaces of a stratum at altitudes of 80m and 35m,
respectively. A vertical bore-hole at S reveals the top surface of the stratum at an altitude
of 50m. The strike of the stratum is north 65° west (i.e, 65° west of north).
Determine the dip and thickness of the stratum.
Scale 1 : 1000
