Safecrete Headings is a wireless shotcrete strength monitoring system that replaces manual testing with embedded IoT sensors and real-time maturity analytics. It eliminates the need for personnel to enter unsupported headings, while giving operations the data to clear headings faster and with greater confidence.
The Problem
Heading development is the backbone of underground mine progression. Every advance follows the same cycle: drill, blast, muck, support, spray, cure, verify, repeat. The curing and verification stages are where the cycle stalls. After shotcrete is applied, the heading sits idle while the mix develops sufficient compressive strength for safe re-entry, typically to the 1 MPa threshold. During this window, there is no visibility into what is happening inside the curing shotcrete.
The conventional approach to strength verification is the penetrometer test. An operator enters the heading under partially supported ground and manually drives a probe into the shotcrete surface at several accessible points. This provides a localised, surface-level reading at a single moment in time. It cannot assess the backs (roof), where fallout risk is highest, and it tells you nothing about the bulk of the applied volume.
The results are inherently inconsistent. Operator technique, probe condition, test location, and surface variability all introduce error. Near the critical 1 MPa threshold, these factors can mean the difference between a pass and a fail. There is no continuous record, no trend data, and no ability to audit the decision after the fact.
The operational cost is significant. Without real-time data, re-entry timing is based on conservative estimates and site experience. Headings are routinely left idle longer than necessary, and crews, equipment, and ventilation schedules back up behind the bottleneck. Every hour of unnecessary delay cascades through the mine plan.
The Solution
Safecrete Headings uses single-use wireless sensors that are embedded directly into the shotcrete during the normal spray cycle. Each sensor continuously measures the temperature profile of the curing mix and broadcasts data via long-range RF to an edge gateway positioned outside the heading. The cloud platform applies the maturity method (ASTM C1074) to calculate real-time compressive strength from the temperature-time history, calibrated against the site’s specific mix design. When the configured strength threshold is reached, automated clearance alerts are sent directly to dispatch.
Key Capabilities
Deployment
Safecrete sensors are single-use consumables. An operator activates the sensor with a magnet swipe and drops it into the shotcrete hopper during the normal spray cycle. No drilling, no mounting hardware, no infrastructure modification. The edge gateway is a portable unit positioned outside the heading to receive RF data. Deployment adds no time to the existing spray process and requires no specialist training.