Mining shaft Fiber optic monitoring of the R VIII
Thursday 29th april 2021
Mining shafts are located in areas affected by mining exploitation or mining bumps and must be monitored to avoid damaging their housing and instrumentation. Some of these shafts are monitored by traditional methods such as precise leveling, Total Stations but fiber optic monitoring is not common in this sector.
Here, the goal will be to monitor by means of fiber optic instrumentation this mining shaft. This type of instrumentation is not common and is here a great advance in mining shaft monitoring.
Installation of the optical fibers:
The optical fibers were installed in the mining shaft by KGHM teams and then Cementys teams came to check the condition of these lines and to perform the first measurements. Three measurement campaigns are planned every three months following the calibration phase. The purpose of these different phases will be to qualify the system and to monitor it over the long term.
This project being one of the first to implement fiber optics in a mining shaft, the first step is to verify that the data obtained are in accordance with the expectations and the results given by the sensors already in place. The installation in difficult to access areas such as this one is also a major challenge. Indeed, access to the shaft is limited by the different operations taking place inside it. In addition, operations that may be simple in laboratory conditions are much less so underground and in small spaces.
Implementation by Cementys:
The instrumentation set up in the framework of this project consists of placing 3 optical fibers distributed at 120° around the circumference of the mining shaft in order to monitor any movements of the latter. The objective here is to follow the mining shaft in the long term in order to compare it to measurements already made by traditional methods but also to detect possible anomalies in this shaft.
Within the framework of this project, the aim is to instrument a zone between -360 and -530 m in the mining shaft. The optical fibers mentioned above run through this zone and are connected to the surface by a telecom cable used solely for data transmission. Thus, Cementys engineers have access from the surface to the monitored places on the shaft housing in order to carry out the measurements. Ultimately, it is planned to deformation monitoring of the shaft housing online in real time.