The art of pit de-watering
One of the most important activities conducted by Fomento Resources’ ground level team at Cuddegal mines is the removal of accumulated rain water after the monsoons.
This annual activity termed “de-watering” is conducted with great precision and safety. It is critical to the alliances operations for two reasons - Firstly, the requirement of a dry pit for the mineral operations process to commence and secondly for the water to be removed, treated and utilized in a systematic manner.
2.5 million cubic metres of rain water is estimated to accumulate in the main mining pit of Cuddegal over the monsoon in addition to the seepage of underground water, making the de-watering task a challenging one.
De-watering is carried out by two diesel operating pumps - a pontoon pump which floats on the water and a ground pump on shore. Both pumps jointly pump out 2200 cubic metres of water per hour and operate for close to 20 hours a day. It takes four months for the water to be removed.
Adequate safety precautions are ensured during this operation for both man and machine. Pump operators are trained in swimming to ensure that there are no accidents and the offshore diesel pump situated on the edge of the pit is fenced with ropes to prevent any operator from toppling over.
Simultaneously, proper usage and discharge of water is carried out. At the discharge point, the pumped out water is treated with lime solution. From here on, it is channelled through a series of settling ponds to remove impurities in the water. From each of these ponds, the treated water is pumped to the beneficiation plant where ore is processed. The Alliance uses rain water for this very important activity of ore processing instead of drawing on external water plants.
The treated water, in excess of what is required for the plant flows through a 1.5 kilometre channel and joins the river. Communities in the adjoining areas make use of this water for some of their irrigation needs.
Excess water poured into a storage area from an overhead pipe to be used for spraying roads
Meanwhile, a portion of the excess water at the discharge point flows from an overhead pipe (similar to an overhead shower) and collected in a little pool. This water is then used to spray the roads and pathways in the mining areas to keep them moist and dust free.
The art of pit de-watering goes beyond taking accumulated water out of the mining pits. A carefully regulated process helps in proper environmental management and cautious use of excess water.