A method for the extraction of a mineral from an underground unconsolidated formation comprises the steps of:(a) driving a casing through the overburden and into the mineral bearing pay zone,(b) passing a high pressure water jet head and associated supply line down through the casing so that an annulus is formed between the casing and the supply line and the jet head projects just beyond the casing,(c) directing water from the jet head into the pay zone to cause disintegration of the latter,(d) recovering desired product through the annulus between the piping and the casing,(e) moving the jet head to a different level in the pay zone when the previous level is effectively exhausted, and(f) moving the casing in association with the jet head so that the latter remains in the same operating position with respect to the casing with the jet head projecting just beyond the casing.The method is particularly suitable for extracting bitumen from tar sands.