M3103 - Solution potash mining, sodium sulfate production, manufacture tobacco products

Operational Details
In this process, heated brine is pumped down through old underground workings created by over 30 years of potash mining.

Warm brine dissolves the potash that is exposed along the walls of the mine openings. The brine is heated by means of natural gas fired heaters that raise the brine temperature slightly higher than the average formation temperature. The injection temperature is important, because the rate of dissolution increases with the temperature.

The warm brine is pumped to a header system that then pumps the brine to the well shaft or piping. The brine travels up the well, dissolving potash as it travels through the workings, and is pumped to the surface through an oil-type well and discharged into a large settling pond. The potash drops out of the solution when the cold water chills the solution. The potash is then dredged from the floor of the settling pond and transported to the mill where it is processed using conventional means.

A large advantage in this process is that it is not as intensive as the conventional underground mining of potash, which needs approximately 50% of the workers to recover the potash. However, recovery costs are offset somewhat by the lower yield from using the solution mining process.

An injection well process is also used when in-flow of water is a problem. This condition results from water entering the column or dig at a rate that cannot be pumped out. When this occurs and the water cannot be frozen, then the solution method must be used.

SIC Codes
000000507 - Solution potash mining
000000566 - Sodium sulfate production
000000923 - Mfg of tobacco product