Overhead Shotcrete

When you say overhead, people invariably think of fixed costs, salaries, and the general costs of running a business.

Robotic Shotcrete Applications for Mining and Tunneling

If a robotic applicator is mentioned in connection with mining or tunneling and shotcrete, what is meant is an apparatus used to hold and control a spraying nozzle. Why should this be necessary when a man can do the same work? Tunneling and mining development are intrin-sically hazardous forms of construction. When shotcrete is used as initial temporary support after blasting, using a mechanical arm to extend into an unsupported area is a great enhancement to personnel safety.

Underground Shotcrete Quality Assessment

During the 1990s, the use of dry-mix shotcrete as a tool for ground support became much more prevalent in Canadian hardrock mines. With this increase in dry-mix shotcrete use came the need to develop a practical and accurate method for determining the quality of the in-place shotcrete. This report summarizes the results of a study undertaken to provide the basis of an under-ground shotcrete quality assessment program for hardrock mines.

Early-Age Test Methods for Fiber-Reinforced Shotcrete

Toughness is at least in part influenced by the compressive strength of the shotcrete matrix, so concrete strength is doubly important for ground control. In time-critical environments such as heading development in mines and most tunnels, the cost of excavation is often strongly influenced by the overall rate of progress; this, in turn, is influenced by the time to safe reentry. The minimum period of time that must elapse before it is safe to reenter under freshly shotcreted ground is directly related to the rate of strength gain in the shotcrete matrix.

Reentry into a Shotcreted, Underground Heading

Whether in a mine or a tunnel, the concept of keeping all people working under supported ground is an essentially sacred one. Even with the most stable ground, the risk of a ground fall causing injury to persons or possessions is greatly mitigated once proper support measures are installed. This becomes even more critical as the quality of the ground diminishes.

Quality Management of Shotcrete in North America

As for all construction materials, a proper program of quality management should be implemented in shotcrete construction to protect the owner™s investment. This article briefly examines typical shotcrete Quality Management (QM) practice in North America. QM can be considered to be comprised of Quality Assurance (QA) and Quality Control (QC) functions.