Abstract

The Thyssen Mining Group of Companies has successfully applied ground freezing technology to numerous projects throughout Europe and North America for over 100 years. Recently, the aspect of data acquisition and data verification has received greater focus.

Thyssen Mining has been engaged in several relatively deep shaft sinking projects over the past five (5) years, all of which have required ground freezing to successfully sink through water bearing rock. To safely and economically sink through a quantity of water similar to Saskatchewan's Potash Mines, it is imperative to understand freeze wall thickness and growth rate.

Critical to understanding freeze wall thickness and growth rate, is the collection of accurate data as well as the interpretation of those data. The data can then be utilized to gain a better understanding of the freeze wall growth rate in active projects as well as to provide data to be utilized in modeling for future projects.

This paper elaborates on the installation and operation of the data acquisition system utilized at the Newmont Leeville project, Nevada's first frozen shaft project.

In addition, this paper elaborates on the methodology developed by Thyssen Mining to manipulate the freeze wall data derived through the data acquisition system.

The successful incorporation of the new system of collection and analysis of freeze wall data for the Leeville Project has given Thyssen Mining a high degree of confidence in the understanding, as well as prediction, of the ground conditions during shaft sinking.

This paper will include:

  • A brief description of ground freezing and its objective;

  • An overview of previous data acquisition methods employed;

  • Current data acquisition methods;

  • Installation requirements; and,

  • Data manipulation and presentation methods.

Introduction

Thyssen Mining Construction of Canada ("TMCC") was chosen by Newmont to sink a ventilation shaft (Leeville No.3 Ventilation Shaft) at its Leeville underground mining operation located on the Carlin Trend approximately 40 kilometers North of Carlin, Nevada. A major contributing factor in the selection of TMCC was the company's extensive experience in sinking shafts through frozen ground.

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