Mining Pit Reclamation using Over-Pond Evaporation System Becomes Working Solution

Rain for Rent received a phone call from a customer to purchase six Big Gun sprinklers to irrigate the banks of one of its former mining pits. This mine produced over 175 tons of gold during its operation from 1988 to 1994. Since then, the mine's owner has been working towards reclamation of the property to its original state. The lake is approximately 25 acres at the surface, with the greatest depth being 370 feet. The customer has to lower the level of the lake several feet from the spillway to ensure the lake does not overflow during the winter season. We discovered that the water cannot be spread elsewhere on site due to some excessive levels of salt and arsenic.

We scheduled a site visit and spoke with the customer regarding several available options. We ruled out the use of Big Guns when determining that the sprinklers wouldn't be very effective because the ground around the lake had a lot of shale rock. In that process, after the topsoil was saturated, the water would just run back into the lake. The customer's pump could only supply two sprinklers at a time, and the pipe and labor to install, operate, and maintain the system did not seem feasible. Rain for Rent proposed an over-pond evaporation system, with floating pipelines and nozzles.

The customer was very receptive to the idea. The system was proposed with an HH-150 feeding a 12” HDPE line on the shoreline, into the 2” HDPE laterals, which would float on the water, suspended by the floating sprinkler assemblies. Our team has a great deal of direct experience with over-pond evaporation. Our foreman moved the system to a part of the lake where we could easily carry aluminum pipe in for the header pipe, and have minimal pressure losses in the mainline.

Once the project was up and running, the pump was set on an automatic starting schedule to run during daylight hours when evaporation rates are at their peak. The inlet flow into the system is 2000gpm and the customer is evaporating up to 400gpm. A very satisfied customer is looking to expand the system for next season.