Mine Water Treatment with a Pilot Scale RAPS-System
In 1985, economic reasons caused the closure of the fluorspar mine “Hohe Warte” near Gernrode in the German Harz Mountains. Though remediation works were conducted in the preceding years, mine water is currently flowing out freely of the dewatering adit and is impacting the environment and the receiving brook. The mine water is characterised by low pH-values, high conductivities and contains considerable amounts of iron, manganese, and arsenic. Annually, the mine discharges 0.7 Mio m of mine water with 7.8 tons of iron, 3.8 tons of manganese and 13 kg of arsenic. Therefore, the discharging mine water has a great potential to affect the quality of the receiving streams and resulted in a decrease of biological diversity. Based on hydrogeological and hydrochemical investigations, a passive treatment system would be able to treat the mine water. In February 2003 a pilot system was installed near the dewatering adit consisting of a settlement pond, a RAPS system and a constructed wetland. It could be shown that this passive system was able to treat an aliquot of the mine water down to ecologically acceptable standards.
Passive Treatment Systems for Acid Mine Drainage
PASSIVE TREATMENT SYSTEMS provide an alternative method for removing metals from acid mine drainage. There are several types of passive treatment systems; they may be used on their own or in combination to treat difficult effluents. The type of system selected is dependent upon the chemistry of the acid mine drainage and the flow of the discharge, as well as State and Federal regulations. Passive treatment systems do not require power and are less expensive than active treatment systems. They also require less maintenance, which makes them advantageous in remote locations.
Thorium in monazite sand; separation and determination by precipitation from homogeneous solution
A new method is described which consists of three steps: (1) decomposition of the monazite sand with perchloric acid; (2) separation of thorium and the rare earths by hydrolysis of methyl-oxalate in acid solution; and (3) separation of thorium from the rare earths by hydrolysis of urea in the presence of formic acid. The authors consider the method to be accurate and rapid.