Located within the Illinois Coal Basin is Knight Hawk Coal’s Viper Mine with both surface and underground operations. With a dock on the Mississippi River, Knight Hawk has immediate access to export their coal both locally in the United States and internationally to the global market.
Viper Mine has been in operation since 1982 as a surface mine, before exploring deposits below ground in 2006. Currently, Viper Coal Mine consists of both underground and surface mines with a carbon recovery operation on site. In 2020 Knight Hawk Coal increased ownership of Viper Mine taking assumed long-term mine closure liabilities including the dewatering of their tailing storage facility.
Viper Mine Dewatering Project
Viper Mine’s tailings storage facility is at capacity reaching the end of Its useful life after 39 years. The current tailings dam has a pool surface area of 85 acres with slurry pool volume sitting at approximately 11,600 square feet. Night Hawk Coal contacted Minetek to assist with the dewatering and reclamation of this storage facility. The entire 270-acre storage facility requires dewatering before reclamation can begin, with around 140 million gallons of water to be removed. The goal for Nigh Hawk Coal’s Viper mine is to be a zero discharge facility ensuring environmental compliance.
Viper Coal Mine Water Challenges
The quality of the Illinois basin water posed a challenge for Viper Mine due to high PH levels, chlorides and sulphates. The pH level ranged between 8.0 to 9.0, with 2000 to 2200 mg/l of chlorides and 3200 3500 mg/l of sulphates.
The permitted pond water quality discharge limits are 500 mg/l of chlorides and 2000 mg/l of sulphates. Viper Mine had the option to discharge “free water” in excess of 140 million gallons. Due to the exorbitant costs of water treatment / reverse osmosis, Minetek’s water evaporators were a cost-effective & efficient long-term solution.
Minetek Water Evaporators
Knight Hawk Coal’s Viper Mine purchased two Minetek 200/100 land-based water evaporators to assist with the dewatering of their tailings dam. In addition to the evaporators, Minetek supplied a high-volume head pump to supply water at high pressure.
Minetek’s land-based evaporators process 400 GPM (gallons per minute) of wastewater at 145 PSI (pound per square inch). Overall Viper Mine was able to achieve an evaporation rate upwards of 30%. Evaporating 120 GPM and 172,800 GPD (gallons per day) at an estimated 80% run time.
Viper Coal Mine Tailings Dam
Viper Mine was able to reduce water levels of the tailings storage facility by over 2ft over a 4-month period. The total wastewater reduction is approximately 38 million gallons, with 20 million gallons attributed to Minetek’s water evaporators.
Minetek offers the world’s largest and most cost-effective water evaporation technologies, suitable for a diverse range of climates and operating conditions. Our water management solution removes the need to discharge water into the environment, or rivers, creeks and streams. If water is evaporated at the source the risk of outside environmental contamination is eliminated. This environmentally friendly solution ensures compliance and lowers the risk of pollution to the waterways and ecosystems.
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