The invention relates to a pretreatment or process prior to ore flotation, which allows the total or partial extraction of bitumen or other organic elements that form part of the ore and which interact negatively with the flotation process. The pretreatment consists of mixing the ore with water and adding a strong base. Following a period of agitation and bubbling, the organic elements are separated, said elements rising to the surface owing to the hydrophobicity thereof and being removed. Ore particles of economic interest are also removed together with the organic elements. For this purpose, cleaning steps that allow the ore to be returned to the process are considered. When the pretreatment is complete, the ore has a lower content of organic elements, which facilitates the ore flotation process and improves the indicators thereof: recovery, concentrate grade, and use of reactants.