(5) If, after the medical treatment, the person referred to in sub- section (4) is declared medically unfit to discharge the duty which he was discharging in a mine immediately before presenting himself for the said examination and such unfitness is directly ascribable to his employment in the mine before such presentation, the owner, agent and manager shall provide such person with an alternative employment in the mine for which he is medically fit: Provided that where no such alternative employment is immediately available, such person shall be paid by the owner, agent and manager disability allowance determined in accordance with the rates prescribed in this behalf: Provided further that where such pehson decides to leave his employment in the mine, he shall be paid by the owner, agent and manager a lump sum amount by way of disability compensation determined in accordance with the rates prescribed in this behalf.