Stability Analysis on the Long-Term Operation of the Horizontal Salt Rock Underground Storage

The construction of the vertical cavern in the salt dome deposit can meet the requirements of both storage capacity and tightness. However, if the vertical cavern is still used as the design shape of the salt rock underground storage in the layered salt rock deposit, the high design capacity cannot be guaranteed while the tightness is satisfied. In this case, the use of a large-span horizontal cavern as the design shape of the salt rock storage can not only effectively increase the design capacity of the storage, but also solve the problems such as the stability and tightness of the storage during the operation period by improving the structural form and working mode. Based on this, the ellipsoid-shaped horizontal salt rock underground storage is taken as an example, and a single-cavern horizontal salt rock underground storage model with different diameter-to-height ratios is established by using FLAC3D software. The change law of vertical and horizontal displacements, volume loss rate, and plastic zone distribution of salt rock storage changing with the diameter-to-height ratio are studied, and the optimal diameter-to-height ratio is determined. And then the long-term operation process of the double-cavern horizontal salt rock underground storage under the optimal diameter-to-height ratio is simulated, and the optimal pillar width is obtained.

Self-sealing capacity of argillite samples

Many countries are currently facing the issue of finding a proper solution to store radioactive wastes coming from nuclear energy production plants. The possibility to store them in underground tunnels is largely considered and investigated. In France, Andra (Agence Nationale pour la gestion des Déchets Radioactifs) selected the Callovo-Oxfordian rock clay (COx) situated in the Meuse/Haute Marne site (France) between 400 and 600 m depth as possible host rock deposit. The excavation of the storage tunnels is expected to create a fractured zone around galleries. However, the factures will be then gradually re-saturated by the underground water coming from the surrounding rock mass and the fractures are expected to self-seal in contact with water, thanks to the swelling potential of COx. The capacity of self-sealing of COx, i.e. closing of fractures after water contact and possibly restoring of hydraulic permeability, is thus of primary interest for the safety of the storage system with respect to water, gas and solutes transport. In the work presented in this paper, the self-sealing behaviour of the COx argillite was investigated through x-ray tomography. The tested samples show significantly different responses depending on the zone where they have been collected on site. The results of mineralogical analyses (x-ray diffraction) are used to understand the observed phenomena.

Experimental Study On The Durability Of Hotmix Cold Laid Asbuton As Asphalt Porous with Cantabro Test

Natural Asphalt from Buton Island can be used as a substitute material for petroleum asphalt, which is known as asbuton. Asphalt Buton (Asbuton) is natural asphalt that contained in the rock deposit located in Buton Island and surrounding areas. Natural asphalt at the Buton Island (asbuton) has a huge deposit for a binder in asphalt mixture use. Many attempts have been carried out to improve the utilization of Buton asphalt as a binder in asphalt pavement road. One of them is the technology development of Buton asphalt pre-mix by adding fluxing materials (modifiers) that serves to soften the bitumen asbuton into the appropriate characteristics as a binder in the asphalt mixture. By adding the fluxing materials, asphalt mixture can be durable even spread and compacted at the cold temperature. This mixture is very useful in areas that have limited asphalt mixture production (AMP) such as in the isolated and small islands in Indonesia. In the pre-mixed Buton asphalt, the mixing is produced on the manufacturing asphalt mixing plant (AMP). After mixing, it can be stored or packaged, while rolling and compaction procces in the field can be performed at cold temperature. The test results of cantabro with the same level of 5.5% BGA and 3.5% flux oil showed that the mixture satisfy the requirements of the asphalt porous mixture according to REAM (Road Engineering Association of Malaysia), which is maximum of 20%.

Method for the Evaluation of the Reserve of a Metallurgical Quartz Deposit by Advanced Kriging Techniques

There are several different methodologies for the evaluation of the reserve of a mineral deposit. Traditionally, classic methods of volume computation for mineral deposits have been used to evaluate the reserve according to its commercial quality. Nevertheless, in previous works it has been demonstrated the functionality of the advanced kriging techniques applied to granite batholiths. Comparing fuzzy kriging techniques with universal classical kriging, it was concluded that the fuzzy techniques had good results for planning the selective mining of the ornamental rock deposit. Since geostatistical methods had good results, these techniques are applied to a metallurgical quartz deposit in this work. The objective of the investigation is to develop the most adequate technique for the determination of the different material qualities in this type of deposits, where the chemical composition of the mineral (aluminium oxide and impurity contents) mainly determines the grade. The obtained results show that the compositional kriging technique is more adequate than fuzzy methods for this type of deposits, allowing a sufficiently coherent prediction of the distribution of grades in the deposit. Based on the results, a 3D geostatistical model composed of cubed cells was done as well. The model provides a visual tool, easy to put into practice for the exploitation management. Keeping all this in mind, the selective mining of the reserves would be possible, being that fact necessary to compete in the rising, competitive world market.