A method for recovering alkali values from at least one cavity of an underground ore formation, said ore comprising trona and/or wegscheiderite, said method comprising: - carrying out an ore dissolution phase (a) into the at least one cavity, said ore dissolution phase comprising dissolving in situ at least a portion of ore from an ore face of the cavity into a first aqueous solvent to form said a first liquor comprising sodium carbonate and to deposit sodium bicarbonate on at least a portion of the ore face; and - removing the first liquor obtained from phase (a) from the at least one cavity of the underground ore formation to the ground surface; - and carrying out a cavity cleaning phase (b) into the same cavity where the ore dissolution phase (a) took place in order for at least a portion of said deposited sodium bicarbonate to be removed from the ore face, said cleaning phase (b) comprising dissolving in situ at least a portion of the deposited sodium bicarbonate and optionally dissolving in situ at least a portion of the ore from the ore face into a second aqueous solvent to form a second liquor comprising sodium carbonate, said second aqueous solvent having a surface parameter before injection into the cavity, selected from the group consisting of pH, hydroxide concentration, temperature, and any combinations of two or more thereof, which has a higher value than the first aqueous solvent used in the dissolution phase (a); and wherein said 'surface parameter' identifies a parameter of a solvent at the ground surface before injection into the cavity, and - removing the second liquor obtained from phase (b) from the at least one cavity of the underground ore formation to the ground surface; and - repeating the ore dissolution phase (a). - carrying out an ore dissolution phase (a) into the at least one cavity, said ore dissolution phase comprising dissolving in situ at least a portion of ore from an ore face of the cavity into a first aqueous solvent to form said a first liquor comprising sodium carbonate and to deposit sodium bicarbonate on at least a portion of the ore face; and - removing the first liquor obtained from phase (a) from the at least one cavity of the underground ore formation to the ground surface; - and carrying out a cavity cleaning phase (b) into the same cavity where the ore dissolution phase (a) took place in order for at least a portion of said deposited sodium bicarbonate to be removed from the ore face, said cleaning phase (b) comprising dissolving in situ at least a portion of the deposited sodium bicarbonate and optionally dissolving in situ at least a portion of the ore from the ore face into a second aqueous solvent to form a second liquor comprising sodium carbonate, said second aqueous solvent having a surface parameter before injection into the cavity, selected from the group consisting of pH, hydroxide concentration, temperature, and any combinations of two or more thereof, which has a higher value than the first aqueous solvent used in the dissolution phase (a); and wherein said 'surface parameter' identifies a parameter of a solvent at the ground surface before injection into the cavity, and - removing the second liquor obtained from phase (b) from the at least one cavity of the underground ore formation to the ground surface; and - repeating the ore dissolution phase (a).