Uncertainty and variability are ever-present in the fields of geomechanics and geotechnical engineering. These uncertainties and variabilities can introduce risk into mine facilities (open pits, underground, tailings storage facilities, etc.). Traditionally, the Factor of Safety (FS) has been used as a measure of anticipated performance. In other words, if the FS meets the acceptance criteria, it is anticipated that the facility will perform in an acceptable manner. However, the FS, by itself, does not communicate anything about risk, nor variability or uncertainty. Reliability methods allow calculation of a Probability of Failure (PF), which can be integrated into a risk assessment. However, a PF assumes that all of the critical elements of a design have been adequately addressed. In either case, the FS and PF, by themselves, are of limited utility if performance measures (deformation, piezometric head, etc.) are not also defined as part of the acceptance criteria. Risk-informed decision-making (RIDM) provides an avenue to make informed risk decisions while providing a platform for defining the acceptance criteria. In this approach, there is a direct link between risk and performance. The RIDM process also allows the risk and acceptance criteria to be updated periodically, so that changes in the operation and/or performance can be considered. This approach is in contrast to the current practice where acceptance criteria are often defined without regard to the site conditions and where risk and acceptance criteria are treated as constants.
Component 2 results for the tailings roadmap study. The objective of the report is to define the important tailings reclamation objectives to which successful tailings technologies should contribute. The report presents the results of a number of workshops and studies used to develop the objectives, sub-objectives and indicator criteria to be used to screen and develop the road map for tailings technology implementation.
These guidelines provide thorough and consistent procedures for selecting and accommodating infow design foods (IDFs), the food fow above which the incremental increase in water surface elevation downstream due to the failure of a dam or other water retaining structure no longer presents an unacceptable additional downstream threat. These guidelines are not intended to provide a complete manual of all procedures for estimating IDFs; the selection of procedures is dependent upon available hydrologic data and individual watershed characteristics.
Systematic assessment of as-built open pit mine slopes is required to verify that slope design criteria are appropriate for the ground conditions and that slope designs are being correctly implemented by mine operations. It is imperative that design bench geometry and inter-ramp slope angles are delivered (in order to meet scheduled production targets), slope design acceptance criteria are achieved, and that geotechnical design risks are appropriately managed, so that the design intent is met. The excavation compliance indicator (ECI) as developed by Seery and Lapwood (2007) and presents a methodology for quantifying compliance to design via measurement of the as-built individual geometrical elements that comprise the bench geometry; i.e. bench face angle (BFA), crest position, toe position and catch bench width (CBW). Measurements of these elements are combined and weighted in order to deliver an overall slope design conformance metric (i.e. the ECI score). The technique enables valuable insights into the contributing factors that adversely affect design implementation conformance, thereby enabling operational practices to be modified in order to deliver improved design achievement. This paper outlines how the Oyu Tolgoi (OT) open pit geotechnical team implements ECI and how it is integrated into their design reconciliation workflow. This paper also provides some recommendations for improving the ECI process.