(b) One method of mining petroleum is drilling:
(i) The underground rocks are sampled and tested for traces of oil
(ii) When oil is discovered, a well is sunk to reach it by the help of a drilling rig or derrick
(iii) The oil is then pumped out
(iv) A system of valves called "Christmas tree" is created to control the flow into tanks
(c) Four problems associated with mining in West Africa;
(i) Lack of fund
(ii) Lack of technical know-how
(iii) Absence of minerals
(iv) Lack of sources of efficient and reliable power