– Patented methods for monitoring and surveillance of rock bolts
World-wide, about 100 million grouted rock bolts are installed annually, most of them underground, some to reinforce rock slopes. Water in cracks and insufficient grouting are problems that can result in corrosion and later on to bolts breaking.
These are old-fashioned and unnecessary risks in an already risk-filled environment.
Now there is a technique that makes it possible to expose problems before they lead to negative consequences.
Optimal safety requires completely grouted rock bolts. With Rock Safety System’s patented Cavi products you can “see below the surface”. With CaviTube mounted on the rock bolt you can monitor and document the installation. If you also choose CaviBasic, and combine it with your choice of sensor technology, you can also continuously monitor how the bolt stretches under many years to come. This saves time and money as well as increasing accessibility and safety. Link to our leaflet (PDF)
This method fits almost
all rock bolts
Mines, road and train tunnels, rock cavities or rock slopes. Longevity, safety demands and accessibility varies – this is why we offer custom tailored solutions!
The Cavi method saves time and money
How do you know that the rock bolt is correctly grouted and how do you know the status a few years later? It is hard to know if the bolt is fully injected, if a bolt has broken off inside the rock mass or how much elongation has occurred along a dynamic bolt inside the rock.
Installation monitoring and status surveillance of grouted rock bolts have been problems for a long time. CaviMeter and our sensor program solve these problems and fit all types of cement-grouted rock bolts.
Rock Safety System’s Cavi products for grouted bolts are unbeatable for monitoring and documentation of installation as well as the surveillance/analysis of rock bolt status over time.
No other system provides information with such precision and in a so accessible manner.
It is a direct-measuring method, in contrast to other alternatives.
With the Cavi method, the volume is measured by observing a drop in pressure. You get the results of the measurements immediately, without detours, via analyses and assumptions. Right away you can see whether the rock bolt is fully grouted or not.
There is a significant savings potential in ensuring correct installation. The reduction in manpower hours and avoiding drift stops is the result of choosing the detection method for status monitoring that fits your needs.
But most important is the increased safety in a risk-filled environment that all work underground entails.
This is how it works
CaviMeter works by fitting the rock bolt with a thin plastic tube with two small slits. When the bolt has been installed the tube is pressurized with gas to detect any cavities or cracks. If there are any cavities in the injection grout, the gas will fill the cavities and the measuring equipment calculates their size.
Those who choose the simplest sensor, CaviBasic, have a wider range of possibilities. A metal wire is then fitted inside the plastic tube to also allow for status surveillance over time and with your choice of detection method. In this case, we offer CaviLight, CaviSense and CaviCom that show the status of the rock bolt in different ways.
Installation monitoring of grouted rock bolts
With CaviMeter, the installation of grouted rock bolts can be securely monitored and documented. A plastic tube is fitted along the bolt and the installation is pressurized with gas to discover and measure any crevices.
CaviBasic is a further-developed version of CaviMeter that enables the user to monitor the status of the rock bolt over time. CaviBasic must be chosen at the start of installation.
Status surveillance of grouted rock bolts
A plastic tube with small cuts is fitted on the rock bolt to enable installation monitoring. Within the tube there is a thin metal wire that enables status surveillance. For rock bolts with CaviBasic, there are three alternatives for reading the information on bolt status. All three have sensors are completely sealed in plastic and can take tough underground environments.
CaviLight is a sensor that is screwed on to the thread of a rock bolt. When the sensor comes in contact with the end of the bolt, the sensor’s electric unit switches on. Bolt breakage is indicated by a flashing red LED. Bolt elongation is measured manually or by a fluorescent bead falling down from the sensor when a pre-determined elongation is reached.
CaviSens is a sensor that is screwed on to the thread of a rock bolt. The sensor indicates bolt breakage by a flashing red LED and elongation by a flashing yellow LED if an adjustable, pre-determined elongation is reached.
CaviCom has an energy-efficient power unit that communicates with your internal network and enables presentation of rock bolt status on a central computer.
Product film from Rock Safety Sweden
Watch this film about the patented Cavi method. CaviMeter works by fitting the rock bolt with a thin plastic tube with two small slits. When the bolt has been installed the tube is pressurized with gas to detect any cavities or cracks. If there are any cavities in the injection grout, the gas will fill the cavities and the measuring equipment calculates their size.
The development project Mining for Generations
This film is about an ongoing development project in cooperation with Atlas Copco, LKAB, Rock Tech Centre, Luleå University of Technology and Rock Safety Sweden.
Research article at international conference
Luleå University of Technologyin Sweden is hosting Ground Support 2016. This is the 8th international conference about Ground Support in Mining and Underground Construction.
Rock Safety Sweden will be presenting a research article: Sensor Techniques to monitor installation and status of rock bolts (Gustafsson, L.K.K.A.). Download the article here (PDF).
“It’ll be really exciting to see how well it can measure the load and deformation in the rock.”
– Lars Malmgren,
Section Manager R&D LKAB
Contact us today!
Rock Safety Systems with the Cavi products are developed and owned by Rock Safety Sweden AB. We are leading systems-technology company within the branch for installation and status surveillance of rock reinforcement within the mining sector, tunnelling in hydro power, road and train tunnels, underground storage facilities, etc.
Please contact us to learn more. We will be happy to visit you with a presentation on how CaviMeter and CaviBasic with their different sensor options can increase safety and reduce costs with help in installation monitoring and status surveillance of your rock reinforcement.
Sales: Göran Remahl +46 70 555 59 10, firstname.lastname@example.org
Technology: Leif Gustafsson +46 70 333 44 22, email@example.com
Rock Safety Sweden AB
972 54 Luleå