Does the underground sidewall station survey method meet MHSA standards?

Abstract

The accuracy of all underground surveying is regulated by the standards described in the South African Mine Health and Safety Act. Four categories of accuracy is described. This pa-per describes the evaluation of accuracy standards of a typically configured sidewall station survey network in a narrow mine tunnel environment. The sidewall system lends itself to re-duced risk exposure and greater efficiency coupled with added redundancy normally not found in standard underground networks. The question is asked whether or not this method of sur-veying will meet the MHSA standards of accuracy that was developed for typical hangingwall traverse type networks. Results obtained from a survey closure using a network of clusters of four sidewall stations demonstrates that under the described circumstances it will provide ac-curacies that are within the minimum standards of accuracy of a Class “A” survey as pre-scribed by the Mine Health and Safety Act. It was found that a survey of the same network using clusters of only two sidewall stations method could not provide the same closure results over longer distances, but that this system lends itself well to Class “C” type surveys for re-connaissance and measuring purposes. Results indicated that the second method of surveying appears to have a greater probability of severe bearing error propagation over distances in excess of 180m and would require regular check surveys in order to strengthen the network. Some of the advantages and disadvantages of the sidewall survey system are discussed to pro-vide a better understanding of the application of this method of surveying on South African mines.