US EPA

1357877 

Technical Report 

Lysimeters Allow Quicker Monitoring Of Heap Leaching And Tailing Sites 

Bond, WR; Rouse, JV 

1985 

NIOSH/00152145 

37 

4 

314-319 

The use of the pressure/vacuum lysimeter, or soil water sampler, for monitoring unsaturated zone water conditions for leachate is discussed. The sampler was originally used as a monitoring and research device for studies in agriculture and soil contamination around landfills. It has since been applied in other areas. Lysimeters are now used to monitor solution loss at mining facilities. In addition, they are used to detect leakage through liners of tailings ponds, heap leach pads, and leachate holding ponds. Their use has proved valuable for collecting baseline data and detecting loss of precious leachate fluid. Different lysimeter designs are capable of moisture sampling from near the surface and down to 300 feet. Lysimeters are also capable of sampling soil moisture or saturation plume contaminants from areas not accessible by conventional water well installations. Lysimeters can usually be installed simply and cost effectively, often without the use of heavy drilling equipment. The basic design of a pressure/vacuum lysimeter chamber consists of a porous material through which the soil is drawn into a collection chamber. Access tubes run from the unit to the sample station at the ground surface. Most units range from 1 to 3 inches in diameter. Teflon or ceramic porous material may be used in the intake portion of the lysimeter, depending on application. Pore size varies with the needs of the installation, type of fluid to be sampled, and type of soil material surrounding the unit. Examples of installation and operation of lysimeters in a uranium (7440611) tailings pond, a gold (7440575) heap leach facility, and on a flood plain to monitor arsenic (7440382) and other contaminants from an old tailings deposit are provided. Whereas a conventional perimeter monitor well may take months or years to detect a leak, a properly placed and installed lysimeter can detect solution leaks of the same magnitude in several days or weeks. 

DCN-138277; Monitors; Laboratory equipment; Safety equipment; Soil sampling; Analytical instruments; Laboratory techniques; Hazardous materials; Porous materials; Soil conditioners; Analytical models; Monitoring systems