The influence of vegetation on leachate generation from solid waste piles produced by mining projects : the Rundle example

Prior to embarking on a course of study leading to the Master of Environmental Studies degree I was employed by Esso Australia Ltd. (Esso) as an Environmental Engineer assigned to the Rundle project. One of the tasks that I undertook in this role was the establishment of the Rundle waste dump leachate program. I was involved in the project definition, construction and installation of the field research station, and with the ongoing modelling by the University of Queensland. As a result of my work with them Esso very kindly offered to make available, for the purposes of this thesis, information collected by the waste dump leachate program. Planning for this thesis commenced in July 1986. One objective was to fulfill the need of the Rundle waste dump leachate program for an investigation into the influence of vegetation on water movement and leachate generation. This had been identified as an area in need of work for some time prior to the start of this project. I have had an ongoing contact with the leachate program in the role of consultant to the project. Esso have also supported four site visits to Rundle to collect data for this thesis. A number of field studies are described in Chapter 4 of this thesis. Some studies were carried out by me especially for this thesis, other studies were carried out for the overall leachate program by myself or other workers. The soil moisture determinations described in Section 4.1 were carried out by a local contractor. The measurements taken in the lysimeters were for the overall program. The other soil moisture determinations taken in study plots 3 to 7 were made specifically for this thesis. I determined the location of the access tubes, installed some of them (with considerable help from Esso and the local contractor) and defined the measuring program. The lysimeter study (Section 4.2), was the key element in the waste dump leachate program. I was extensively involved with this program in my role as Environmental Engineer for Esso and very fortunate that I was able to use the information gained from the lysimeters in this thesis. The runoff determinations (Section 4.3) were originally initiated by me as part of the leachate program with a view to incorporating the results into an assessment of water movement in the vegetated layers. Thus the information obtained from this study was not used until I commenced this thesis. The meteorological data (Section 4.4) comprises a central element of the Rundle waste dump leachate program. One of my responsibilities, both as employee and as consultant to Esso has been the calibration and analysis of the Rundle meteorological data. Most of the information regarding material characteristics (Section 4.5) was obtained from earlier rehabilitation studies. The detailed chemical analysis was carried out for the leachate program. I obtained Leaf Area Index information (Section 4.6) and carried out the vegetation survey (Section 4.7) to obtain data for the thesis. The four site visits which Esso very generously supported were primarily for collection of the Leaf Area Index information and to carry out a vegetation survey.