The Wireline Workshop bimonthly bulletin contains valuable material that can be applied in many areas of mining and mineral exploration.
The May issue touches on procedures for drilling and logging the right borehole, reviews total natural gamma ray measurements, and features an analysis of in situ stress measurements.
Some of the key major points of this issue include:
Drilling the right borehole:
Depending on what data is being logged, drilling with the correct specifications is important. Often times, the orientation of a borehole makes it impossible to take measurements without damaging tools or effecting the accuracy of the data.
This Wireline Workshop issue presents certain problems with boreholes and how they can be prevented through communication and following correct procedures when drilling. Boreholes should be labeled properly and 20-40 centimeters of casing should be present above the surface. They should also be capped when not in use to prevent damage. These practices contribute to successful and accurate surveys in the field.
Total natural gamma ray measurements:
Logging gamma ray typically measures total natural gamma, which is a combination of uranium, thorium and potassium. These are naturally occurring radioactive elements due to the instability caused by the nature of their decay. Getting a good gamma log can be useful tool in determining lithology, as it provides distinction between layers such as shale and sandstone.
It is suggested that a gamma ray probe be ran off-center to reduce the effects of the borehole. This is important to better describe bed boundaries. Gamma ray logging should be done at slower rates to increase the accuracy of the data. The section also describes specific corrections that must be made to gamma ray logs.
In situ stress measurements:
Stress measurements can be used for many applications in mine design, management and safety. Kore Geosystems is featured describing common methods for stress measurement in the field, as well as explaining how using data from an acoustic televiewer can be inverted to obtain stress orientation and magnitudes.
Download the PDF of the May bulletin here or below.Wireline_Bulletin_May_2017