INTRODUCTION During the last decades, the processes of enrichment of sulphide ores have been extensively studied in the geological laboratory. The work was chiefly done on copper, silver, and gold deposits. The secondary enrichment of tin sulphide has not been observed in the field; but it is believed by many INTRODUCTION During the last decades, the processes of enrichment of sulphide ores have been extensively studied in the geological laboratory. The work was chiefly done on copper, silver, and gold deposits. The secondary enrichment of tin sulphide has not been observed in the field; but it is believed by many