Salt mines? No, salt craters

"Look at all those craters" said Pearl, "don't tell me we are on the moon?" "All right" says Pickle "I won't tell you we are on the moon, because we aren't, for instance, there are no people on the moon". "How do you know" asked Pearl, "have you been there?" "We are still in Africa, and those "craters' are called 'male', the large ones and 'female' the small ones". "OK, asked Pearl, "and what do they do?". "Salt" said Pickle, "is one of the most important commodities in Africa. The field workers fill the craters with water, the water leaches the salt out of the earth, the water evaporates and leaves a deposit of salt which is harvested into blocks for distribution and sale. What could be neater than that?".
Said Pearl "I want to go home!".