SMI Sag Flag Roof Monitors: Mine Roof Safety and Ground Control for Canadian Mines

How the SMI Sag Flag roof monitor works

The SF100 SMI Sag Flag Roof Monitor measures roof sag and rock strata separation, providing a continuous visual indication of how much movement has occurred. A reflective flag allows movement to be seen from a distance, while a scale on the plunger provides a reading at the instrument.

This gives underground teams a visible reference when checking monitored locations. Changes can be reported to supervisors and ground control specialists for assessment and action under the mine’s procedures.

Features for underground roof monitoring

Simplified Mine Instruments designs its equipment around ease of installation, interpretation and reliability. The Sag Flag uses straightforward mechanics and a stainless steel body and anchors for underground service.

Its key features include:

• Continuous visual indication of roof movement
• A reflective flag for visibility from a distance
• A scale on the plunger to indicate the amount of movement
• A 25 mm movement range

SMI describes monitoring depths from a few feet to more than 50 feet into the rock. Monitoring depth and movement range describe different aspects of the instrument: depth relates to where movement is monitored within the rock, while the 25 mm range relates to the displacement indicated. The appropriate configuration should be confirmed for the application. Underground Roof Movement Monitor

Supporting ground control in Canadian mines

Roof movement readings are most useful when they form part of a defined ground control programme. The mine’s ground control team should determine where instruments are required, how readings will be recorded and what changes require a response.

Ontario’s guidance on ground control in underground mines, for example, addresses the use of monitoring instrumentation, interpretation of results and communication of ground conditions between workers and supervisors. It also highlights the importance of routine workplace examinations and checks on the effectiveness of ground support.

Within that wider approach, the Sag Flag can provide a local visual indication of movement at a monitored position. It supports ground assessment alongside inspections, engineering analysis and other instrumentation selected for the site. It does not provide structural support or establish that an area is safe to enter.

Choosing an SMI roof monitoring instrument

The Sag Flag is part of a wider range of underground monitoring equipment from Simplified Mine Instruments. Carroll also supplies the Miner’s Helper Extensometer and the Miner’s Helper Remote Readable Roof Monitor.

The Miner’s Helper Extensometer uses a reflective rod activated when a user-defined amount of movement occurs. The Sag Flag provides a continuous visual indication of movement. The remote readable monitor allows data to be gathered from a readout box connected by an electrical cable.

The choice depends on the information the ground control team needs and how it will be collected. Carroll can discuss the SMI range and the standard or customized options available for a project.

Where to buy SMI Sag Flag roof monitors in Canada

Carroll Technologies Group is the exclusive Canadian supplier of SMI Sag Flag roof monitors. For Canadian mining operations sourcing ground monitoring equipment, Carroll provides a direct point of contact to discuss product options and request a quotation.

View the SF100 SMI Sag Flag Roof Monitor or explore Carroll’s Simplified Mine Instruments range. Contact Carroll to discuss monitoring depth, borehole requirements and the configuration specified by your ground control team.