|Refrigeration||Ground Freezing/ Shaft Sinking|
Our customer required ground freezing in support of a potash mining shaft sinking operation in order to prevent water inflow and increase ground stability. Two 20 ft diameter lined shafts will be installed to a depth of over 3,400 ft below surface. The upper 1,600 ft of the ground contains zones of high water content, low strength soil and rock that must be frozen prior to excavation. First carried out on similar deep potash mine shafts in the late 1950's in Saskatchewan, the technique has proven successful.
A total of 35 "freeze pipes", over 1,600 ft long, will be installed on the circumference of each of two 40 ft diameter "freeze circles" at the ground surface. Chilled brine will be delivered to the bottom of each pipe via inner polyethylene pipe and will then flow up the annulus between this pipe and the outer steel casing. With the proper flow we will ensure adequate heat transfer from the ground in addition to heat transfer within the flow path of the brine. The brine will be chilled to -35°C at the freeze plant boundary and will be distributed to each of the freeze pipes via a supply and return main header network. The freezing system will operate continuously for up to three years. The plant will be configured to handle a minimum 1,400TR with a brine supply temperature of -35°C.
Startec designed a portable 1400TR Ammonia Refrigeration package to meet customer chilling requirements, including (5) Mycom two stage compound compressors utilizing a total of 1000HP 4160V electric drive motors, air cooled condensers, shell and tube heat exchangers, and liquid sub-coolers
To discuss your requirements for ground freezing, contact a Startec Industrial Refrigeration Customer Representative at 403.295-5855 or toll free at 1-800-555-9439.