Question 15 of 27: 3.6

Question 3.5 – 3.6 side-cast section sketch (3 marks)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

Approach. One combined cross-section, drawn to the Given data of Question 3.4, carries every item both 3.5 and 3.6 ask for — the exam explicitly builds the two sub-questions as ONE sketch annotated in stages.

The dragline sits on the far (spoil) side of the highwall, its operating radius sweeping from the coal face at the pit floor up and over to the top of the spoil pile. Cut depth is the vertical overburden thickness the machine digs through at the highwall (25 m, Given); stacking height is the vertical rise of the spoil pile above the dragline’s own working level; reach (reach factor) is the horizontal distance from the tub centerline to the farthest point the bucket can dig or dump, expressed as a fraction of the operating radius (reach factor typically 0.85–0.95 of R once boom angle/bucket geometry is allowed for). Pit width (40 m) spans from the highwall toe to the coal-face working edge; the highwall slope (63°) and spoil angle of repose (35°) are the two bounding slope lines of the section; the coal seam (3 m thick) sits at the pit floor.