Acid rock drainage (ARD) is a major environmental issue at mining properties across Canada. ARD has been observed at virtually all types of mining operations including base metal, precious metal, uranium, coal and selected industrial mineral operations. Over the past 20 years, a series of monitoring techniques have been developed to predict the potential for ARD at mining sites and to monitor the acid generating characteristics of mine rock piles. There are a myriad of techniques available but little published data as to which techniques are most commonly used, which techniques are most cost-effective and more importantly which techniques provide the best data.
In order to provide guidance to the industry, the MEND Secretariat issued a contract to SENES Consultants Limited in 1992 to conduct a literature Review of Waste Rock Sampling Techniques. The Review provided a comprehensive list and description of sampling techniques along with a suggested guide to addressing waste rock sampling requirements for the exploration, operation and closure phases of a mining project. The Review did not provide guidance as to what techniques were most commonly applied at Canadian mining properties nor did it recommend any specific procedures as being preferred or industry standards.
In an effort to provide a more interactive review with industry and government, a second phase of the project included a detailed survey of waste rock sampling practices currently being applied at sites across North America, Australia and Europe. These data were summarized and a draft position paper was prepared by SENES which highlighted industry practice and preferred monitoring techniques, where possible. This draft position paper was used as the basis for an experts workshop held in Toronto, 11 and 12 March 1994. This workshop included a panel of 12 experts from industry, research organizations and government and was attended by 18 observers. The detailed proceedings are available on request from MEND. A list of persons who completed the survey and the participants at the experts workshop is provided in Appendix A.
Following the experts workshop, the draft position paper was updated and expanded to form this Handbook for Waste Rock Sampling Techniques. The Review was also updated to include the results of the survey, the information presented at the experts workshop, and any other new information presented in the Handbook.
The Handbook is a concise summary of currently available sampling techniques. It is assumed that the reader of this Handbook is familiar with each of the waste rock sampling techniques described and discussed in the Review. Both the Review and the Handbook are available through CANMET. We recommend that the interested reader read both documents. The Review should be consulted when a detailed description and comparison of waste rock sampling techniques is required. The Handbook should be consulted when a concise summary of sampling techniques available and recommended is required.
In Chapter 2, this Handbook briefly addresses: representative sampling, sampling program design, data management and quality assurance and control.
In Chapter 3, each category of waste rock sampling (chemical characterization, water monitoring, gas sampling, etc.) is discussed in a common format under the following headings:
Possible Methods;
Objectives;
Background;
Rating;
Limitations and Advantages;
Recommended Procedures;
Requirements;
Cost; and
References.
Chapter 4 contains a summary of recommended techniques for obtaining information for: (a) rough cost estimates to be used for decision making regarding management, maintenance, monitoring and closure of ARD sites; (b) prediction (modelling) of potential ARD; and (c) identifying additional sample locations/sample types and associated analyses that should be considered for providing valuable supplementary information for decision making.
