Monitoring of mining induced subsidence through measurement of ground strains with Fiber Bragg Grating sensors
In this paper the application of Fiber Bragg Grating based sensors for the monitoring of mining induced subsidence phenomena is illustrated. A high number of sensors were installed in the pavement of a major highway thanks to the use of Bragg Grating arrays encapsulated in composite rods. The sensors and the associated demodulation equipment provide continuous measurements and allow the immediate implementation of safety measures by the authorities responsible for the highway.
Mining subsidence land survey by SAR interferometry
The overall philosophy of this collaborative project, between Doncaster College. RJB Mining (UK), GEC Marconi Research Centre and Matra Marconi Space (UK), is to improve the accuracy of subsidence prediction models implemented in the mining industry. These models help mine management, in terms of productivity, conformity with regulatory consent, and minimised environmental and economical impacts. However, the models currently produce actual to predicted subsidence results in the range 43%-773%, which then have to be adjusted using local knowledge. The project aims to provide accurate data on elevation change due to mining activity, via the application of radar interferometry with ERS synthetic aperture radar (SAR) data. These elevation change data can then be fed into subsidence models to improve predictions about subsidence. Initial interferometry results are presented showing evidence of subsidence. Validation is underway and preliminary interpretations are offered and discussed.
X-rays and photocarcinogenesis in hairless mice
It is well known that excessive X-ray radiation can cause non-melanoma skin cancers. With the increased incidence of sun-related skin cancer there is a need to investigate the combination of sunlight and X-rays. Immunocompetent C3.Cg/TifBomTac mice (n = 298) were divided into 12 groups. Mice were irradiated with 12, 29 or 50 kV X-rays. The mice received a total dose of 45 Gy. They were irradiated with 3 SED simulated solar radiation (SSR) either before or after irradiation with X-rays. The groups irradiated with X-rays alone, 0, 3, 9 and 10 mice (0, 12, 29 and 50 kV, respectively) developed squamous cell carcinoma. In the groups irradiated with SSR after X-rays the development of tumours was significantly faster in the 50 kV group than in the corresponding control group (175 vs. 194 days, p < 0.001). In the groups irradiated with SSR prior to the X-ray radiation the development of tumours was significantly faster in the 29 and the 50 kV groups than in the corresponding control group (175 vs. 202 days, p < 0.001 and 158 vs. 202 days, p < 0.001, respectively). In conclusion, X-ray radiation alone is a weak carcinogen in hairless mice. There is an added carcinogenic effect if X-ray radiation is given on prior sun-exposed skin or if the skin is sun-exposed after X-rays. We still believe that X-ray radiation is a safe and effective therapy for various dermatological diseases but caution should be observed if a patient has severely sun-damaged skin or has a high-risk sun behaviour.