This document describes an evaluation methodology and suite of guides that can be used to appraise the maturity of different geology-related activities within operations. These guides can be completed by on-site staff members in the form of a survey, or by a visiting professional observing an operation’s behaviours. The methodology is designed to evaluate each activity’s maturity using different methods. There are three key methods: a) the Maturity Index, b) the Task Description and c) Improvement Areas. These methods examine the activity from different angles and should align if the results are consistent. The final results can be combined to produce an overall appraisal of the geoscientific information management environment. <...>

The Shewhart X— and R charts are still the most popular control charts in use today for continuous monitoring of quality data. However, for these charts to function properly, the underlying assumption of normality and independence of data must be satisfied. When either independence and/or normality of data are not present, which is a common feature of ore quality data, an application of the conventional Shewhart X— and R charts may introduce false alarms in the analysis of the data.

Mining reconciliation is the comparison of estimated tonnage, grade and metal with actual measurements. The aims are to measure the performance of the operation, support the calculation of the mineral asset, validate the Mineral Resource and Ore Reserve estimates, and provide key performance indicators for short and long-term control (Morley, 2003). Ongoing, regular and efficient reconciliation should also highlight improvement opportunities and allow for proactive short-term forecasting by providing reliable calibrations to critical estimates. The concept is that of “measure, control and improve”.  <...>

The optimisation of a mining operation requires precise ore grade control, metallurgical accounting, and laboratory sampling protocols, which are implemented by using accurate and flawless sampling systems. Good sampling practices, and sampling technologies in these fields have been historically poor and too many existing sampling systems available on the market are flawed in many ways.

Metal mining operations, in particular gold mining operations, use intensive ore control procedures in order to manage the extraction of ore zones from benches containing both ore and waste material. Typical grade control procedures rely on blast hole samples to indicate ore grade. Statistical techniques and geological controls are then used to create two-dimensional polygons, which indicate zones of material designated as ore. These ore-polygons are calculated using preblast material locations and are generally not corrected for rock movement caused by blasting.

Effectiveness of ore grade control at operating mines depends on both the quality and quantity of the samples used. Therefore, optimisation of grade control procedures requires analysis of sample quality and their spatial distribution. This approach, implying quantitative estimation of both these factors and quantification of their contribution to the grade control errors, was used for comparing two different grade control procedures at the Yandicoogina (Yandi) iron-ore open pit mine, located in the eastern part of the Pilbara region of Western Australia. At Yandi, pisolitic iron oxide mineralisation is distributed within a meandering palaeoriver channel, characterised by abundant clay pods that contain the deleterious components; in particular Al2O3 and SiO2.

The sole reason for a mine to exist is to extract the finite mineral resource. Accurate grade control is critical to the economics of any mine. If grade control is not optimised, then no matter how good the downstream processes are, the full potential of the operation will not be realised. The detailed implementation of grade control varies but typically consists of sampling and assaying to determine the location of the ore zones. A lot of time, money and effort are spent defining the location of the ore as accurately as possible … but then it is blown up! The effect that blasting has on grade control is rarely adequately accounted for when the rock is excavated because there has never been an accurate and practical method for measuring blast movement.

During core drilling, runs of core up to about three metres long are extracted from the core barrel. The extraction process rotates the core randomly, so that once the core is laid out in core boxes its original orientation is lost, although the orientation of the core axis is generally known. Various down-hole surveying techniques are available for this, and the common usage of 3-D modelling software has lead to holes being generally very well surveyed. <...>

Монография Австралазийского института горного дела и металлургии посвящена описанию и обобщению самого передового опыта в области оценки минеральных ресурсов и рудных запасов. Настоящее издание состоит из 9 глав и 79 статей, написанных известными в мире учеными и практиками, в которых рассматривается широчайший спектр вопросов, касающихся в той или иной степени очень сложной и актуальной для любой горной компании проблемы оценки ресурсов и запасов. В книге можно найти много полезных сведений о новациях, иногда коренным образом отличающихся от российской зарегламентированной действительности в этой сфере. Книга будет полезна специалистам, работающим в геологической и горнодобывающей отраслях, а также аспирантам и студентам горных вузов.

What is the quality of the sample and assay data? Am I confident enough in my data to be able to make a potentially costly decision? These are the types of questions which should be asked when dealing with assay data.