Development of a Simple Scheme to Determine the Chemical Toxicity of Mine Wastes

Abstract

A decision tree that uses simple physical and chemical tests has been developed to determine whether a mine waste poses a toxicity threat to the aquatic environment. For the chemical portion of the tree, leachate tests developed by the US Geological Survey (USGS), the Colorado Division of Minerals and Geology (CDMG), and modified 1311 TCLP test of the EPA have been extensively used. The multi-element power of modern inductively coupled plasma, atomic-emission spectroscopy (ICP-AES) is also a necessary component of the scheme. At two sites in Colorado, Virginia Canyon in the Idaho Springs/Central City Superfund Site and in the Upper Animas River Basin, 25 sediment samples and the water flowing over the sediments were collected. General analytical measurements were made in the field, and then, the water and extracts from the three leachate tests were analyzed for 31 elements by ICP-AES. Then, element concentration pattern graphs (ECPG) were produced that compared selected groups of the elements from the three leachates and the water. When the pHs of the water and the leachate were below 5.0, the element concentration patterns of all four solutions were quite similar and aquatic toxicity from metals such as Pb, Cu, Zn, Mn and Al was clearly indicated. When the pHs of the water and the leachate were above 5.0, the element concentration patterns from the four solutions were different and inferred aquatic toxicity depended on the leachate test. Usually when there was a difference, it was found that in the TCLP test, elements from carbonate minerals and oxides dissolved and these elements in the CDMG and USGS tests were not as readily released from solution. In a study done in 2002 in Russell Gulch near Central City, CO, that rated mine waste piles, it was necessary to rate the contamination possibility of the piles on separate physical and chemical scales for the most complete assessment.

Assessment of waters and sediments impacted by drainage at the Young Dong coal mine site, South Korea

“…The sediment sampling was performed using the composite method (Smith et al 2000). Three different test methods were used to evaluate the leaching potential of metals: (1) the Toxicity Characteristic Leaching Procedure (TCLP) (EPA Method 1311 1992), (2) the US Geological Survey field leach procedure (USGS-FLT), and the Colorado Division of Minerals and Geology (CDMG) leachate test (Herron et al 1999;Wildeman et al 2003). The metal analysis of water samples and leachate extractions was analyzed using ICP-AES (Perkin Elmer, Optima 3000).…”

Assessment of Young Dong tributary and Imgok Creek impacted by Young Dong coal mine, South Korea

“…The first two tests are based on extraction with deionized water and have been developed by Colorado School of Mines (CSM) and the US Geological Survey (USGS) to provide simple and inexpensive methods to assess mine wastes (Wildeman et al 2003(Wildeman et al , 2007. Hageman et al (2005) found that the major source of variation in leaching results arises in the sampling of heterogeneous waste piles, even though the recommended 30 sample composite method of sampling was used (Smith et al 2000).…”

A Simple Scheme to Determine Potential Aquatic Metal Toxicity from Mining Wastes

“…The idea of what should be included in a standard physical assessment of a mine site was developed in conjunction with two regional projects performed by personnel from the CDMG and CSM (Herron et al, 2001;Wildeman et al, 2003). For mine waste piles, a number of on-site observations are made, including the approximate longitude and latitude of the site, the volume of the pile (estimated by measuring the surface exposure using a tape measure and then estimating the depth of the pile), and the presence and hardness of crusts (Herron et al, 2001).…”

“…A preliminary scheme was published three years ago . Since that time, the approach has been further developed and has been used to assess a number of mine sites and two abandoned mining regions (Heflin et al, 2004;Bazin et al, 2003;Wildeman et al, 2003;Moehle et al, 2005;Steele and Wildeman, 2005;Hageman et al, 2005). These projects have reinforced the basic structure of the MWDT that is shown in Figure 1 and have helped to standardize the procedures when the paste pH or leachate pH value of a mine waste material is around the critical value of 5.…”