Selection Criteria for Open Pit Production Equipment–Payload Distributions and the ‘10/10/20’ Policy

摘要

The aim of this study is to examine the volumetric and mass movement characteristics of load and haul operations using statistical modelling of relatively large samples of bucket loads that are transported as small samples in the form of truck payloads. Generally, the factors infl uencing bucket load variability are random, diffi cult to predict and to control. In the process of loading trucks the underlying variability of individual bucket loads will determine the variability of truck payloads. Bucket loads of material prepared by drilling and blasting for loading into trucks are fundamental quantities in open pit mine production. A study of payload data from a large surface mining operation indicates that bucket loads and truck payloads that are a small sample of bucket loads are normally distributed. Truck payloads have a reduced dispersion compared with bucket loads that is an inverse 0.5 power function of the number of passes per truck payload. Comparison of statistical modelling results with the ‘10/10/20’ policy promoted by Caterpillar Global Mining Inc, indicate that compliance with the ‘10/10’ part of the policy, applying to truck overloading is facilitated, as the coeffi cient of variation of truck payloads decreases, as a result of the increasing number of loading passes. Compliance with the more stringent ‘20’ part of the policy, relating to safe steering and braking is also facilitated, albeit at lower coeffi cient of variation for similar reasons.