To safeguard the delivery of energy supply from coal fired power stations, (CFPS) a stock back up tonnage of coal is required at the station. This stock is generally referred to as a stock pile (SP) whether measured in tonnage (SPT) or in days (SPD). The total stock reflects the stock of coal (in tonnes) at hand, plus the replenishments (such as from stathes [e.g. bunker type] or direct-supply); therefore the total stock is equivalent to the SPT. Essentially, the SPD reflects the daily SPD variation on the stock, based on the daily usage and replenishment… (more)