Amphos 21 has developed several projects during the last years for San Rafael, one of the most relevant tin mines worldwide, property of Minsur. Projects were related to improvements in the water cycle of the operation, ranging from the development of baseline hydrological, hydrogeological, and geochemical studies, particularly focused to integrated water management and effluent treatment, environmental permitting or inputs for engineering mine components (waste and tailings facilities), underground mine drainage and tailings dewatering, framed in reuse and processing of existing tailings (B2 Project). In the same way, support studies have been developed for decision making in future initiatives and expansion projects of the operation.