Sudden falls of large-area hard roofs in a mined area release a large amount of elastic energy, generate dynamic loads, and cause disasters such as impact ground pressure and gas outbursts. To address these problems, in this study, the sleeve fracturing method (SFM) was applied to weaken a hard roof. The numerical simulation software FLAC3D was used to develop three models based on an analysis ...

This paper describes a propagator matrix formulation for the problem of the Stoneley wave propagation in an irregular borehole. This is based on a simple one-dimensional theory that is possible for the low frequency Stoneley wave, because it is a guided wave with no geometrical spreading in the borehole. The borehole and the surrounding formation are modeled by multi-layers discretized along th...

Compositing of borehole assay intervals based on economic aspects is a primary step when the crosssectional method is applied in orebody modelling and mineral resources estimation. The compositing is important because the resulting ore composites eventually determine the outlines of orebody models. However, numerous boreholes and borehole intervals make ore compositing tedious and timeconsuming...

The attenuation of borehole Stoneley waves across a permeable structure (e.g., fractures or fracture zone) is correlated with the permeability of the structure. Using a simplified Biot theory, the structure can be modelled as a permeable porous layer intersecting the borehole. In order to study the effect of such a structure on Stoneley waves and to evaluate the theoretical model, we performed ...

Electrode logging as known in the oil industry is a method for determining the electrical conductivity distribution around a borehole or between two boreholes from the static-field (dc) measurements in the borehole. In this paper , we discuss the reconstruction of the three-dimensional (3-D) conductivity around a borehole in a highly deviated formation with invasion. At this moment, we have not...

Intermittent operation can improve the coefficient of performance (COP) of a ground source heat pump (GSHP) system. In this paper, an analytical solution to analyze the geo-temperature restoration performance under intermittent operation of borehole heat exchanger (BHE) fields is established. For this purpose, the moving finite line source model is combined with the g-function and the superposi...

We describe a new method to simulate 3D borehole resistivity measurements at zero frequency (DC). The method combines the use of a Fourier series expansion in a non-orthogonal system of coordinates with an existing 2D goal-oriented higher-order self-adaptive hpfinite element algorithm. The new method is suitable for simulating measurements acquired with borehole logging instruments in deviated ...

Introduction: At least some meteoritic nano-diamonds are likely of presolar origin because of their association with anomalous Xe-HL and Te isotopic components indicative of a supernova (SN) origin [1,2]. But the abundance of Xe is such that only ~1 in 10 6 nano-diamonds contains a Xe atom, and the bulk 13 C/ 12 C composition of nano-diamond acid residues is chondritic (solar) [3]. Therefore, i...

[1] The Integrated Ocean Drilling Program (IODP) Hole 1301A on the eastern flank of Juan de Fuca Ridge was used in the first long‐term deployment of microbial enrichment flow cells using osmotically driven pumps in a subseafloor borehole. Three novel osmotically driven colonization systems with unidirectional flow were deployed in the borehole and incubated for 4 years to determine the microbia...

[1] Modeling studies suggest that fluid permeability is an important control on the maintenance and distribution of pore fluid pressures at subduction zones generated through tectonic loading. Yet, to date, few data are available to constrain permeability of these materials, at appropriate scales. During IODP Expedition 319, downhole measurements of permeability within the uppermost accretionar...