Adjacent Mass Research Articles

Justification of stability strategy for underground mine openings under higher effective anisotropic stresses

Stability of underground openings is one of the critical challenges in the mining industry. A mine support system design and installation depends on the conditions of mining. This is especially pronounced in the regions of active tectonics with horizontal stresses higher than vertical stresses up to 2–5 times. The tectonic stress-induced activity accompanies even comparatively shallow mining operations. Dense fracturing, spalling and bursting are observed in mines in Gornaya Shoria, or in Apatit JSC mines, at the depths of 150 to 400 m in Russia, at the depth of 260–400 m in uranium mines in Canada, 250 m in Tirol in Austria, or 100–200 m in Norway. As a result of the accomplished studies, the mechanism of fracture zones in adjacent rock mass during heading and mining in high-stress rock mass is defined. The parameters of these zones are determined subject to the rock mass quality, structure and stress–strain behavior. This allows developing the heading technology and mine support system design for the conditions of higher tectonic stresses. The main transient factors capable to affect underground openings are identified, and it is shown that the technology of heading and mine support under dynamic events caused by rock pressure depends on such determinants as: the quality of fragmentation by blasting, blasting sequence, temporary and permanent support designs and lag of the mine support behind the face advance. The proposed approach to the underground mine stability under higher effective anisotropic stresses ensures safe mining at optimal rates of heading.

Radiation exposure to the kidney with interstitial iridium-192 high-dose-rate brachytherapy: Extent and rare morphologic changes of radiation nephropathy.

We sought to investigate functional parameters and morphologic changes of the renal parenchyma after treatment with image-guided brachytherapy using single-fraction irradiation (high-dose-rate brachytherapy - HDR-BT) of primary kidney lesions, and primary and secondary lesions of the liver, lymph node, and adrenal gland close to renal structures. Patients ineligible for surgery were included. We prospectively investigated renal function loss within one year via renal scintigraphy and laboratory parameters (KDOQI stage). Radiation exposure to the kidney was measured by volume receiving 5 Gy (V5). We observed morphologic changes on CT or MRI, with follow-up every three months. In total, 35 patients were included (21 males, 14 females). Eight patients were treated for extra-renal malignancies. The mean V5 of the ipsilateral kidney was 70.0 ±42.4 ml equaling to 44.9% parenchymal volume. After renal treatment, V5 renal volume was 77.8 ±42.2 ml (48.7%) compared with 44.0 ±33.0 ml (32.0%) after extra-renal treatment. No significant reduction in KDOQI stage after 12 months of follow-up were found. Three patients developed morphologic changes in the renal parenchyma, with only one showing a decrease in renal function after 12 months. CT-guided HDR-BT is a viable treatment modality for local ablative treatment of renal and adjacent masses, with no significant reduction of the KDOQI stage as a predictor for complications of chronic kidney disease. However, larger cohorts need to be analyzed to identify vulnerable patients, as in rare cases, plain dosimetry seems insufficient to predict renal function loss after HDR-BT.

Active lateral pressure to rigid retaining walls in the presence of an adjacent rock mass

Active lateral pressure to rigid retaining walls in the presence of an adjacent rock mass

A Multi-year Seasonal Study of Amoeboid Protists in Surface Water at the Margin of a Hudson River Estuary Salt Marsh

Marshes bordering rivers and estuaries are productive ecosystems that interact dynamically with the adjacent water mass. This is a multi-year study (2019–2022) of seasonal changes in the density of naked amoebae in monthly samples from the surface water of the Hudson estuary near Piermont, N. Y. with relationships to key environmental variables (surface water temperature, salinity, Secchi depth representing turbidity, and enterococcus bacterial counts). During the colder months (November to March), when decayed leaves and litter from the deciduous marsh grass produced organic matter in the sediment surface, the mean abundance of active amoebae ± standard error of the mean (SEM) was higher (3.07 ± 0.99 × 10⁴/ L, N = 7). In warmer months (May to September) the abundance of amoebae was lower (1.35 ± 0.29 × 10⁴ / L, N = 10). A multivariate linear regression analysis was performed relating amoeba abundance to four major water mass variables, resulting in the following statistically significant equation (p = 0.03): AD = 0.121 × T + 0.301 × L – 0.047 × S + 0.359 × C, where: AD = active amoebae density (× 10 /L), T = temperature ( C), L = tide level (m), S = Secchi disc depth (cm) and C = bacterial enterococcus concentration (number/ml). In general, given the increasing evidence of the potential importance of amoeboid protists in aquatic ecosystems, further research is warranted on their role in food webs and the carbon biogeochemical cycle within heterotrophic estuarine and coastal waters.

Vibration Effect Induced by Rock Breaking Technology Based on Dry Ice and Energy-gathered Agent in Trench Excavation

Rock breaking technology based on dry ice and energy-gathered agent has been developed and successfully applied in trench excavation for construction of oil pipeline. The vibration velocity waveform induced by this technology was monitored in site test to determine the attenuation law of vibration velocity with hypocentral distance. The results show that this rock breaking technology is effective method of trench excavation. It does not excessively damage the adjacent rock mass, ensuring the integrity of ditch walls. The vibration velocity induced by this technology is decay with the increase of hypocentral distance. At the hypocentral distance of 10m, the vibration velocity reduces to less than 20mm/s, which meets the requirements of the safety standard of blasting vibration in general buildings engineering. The results of this experiment have an important guiding effect on the field engineering practice and application of rock breaking technology based on dry ice and energy-gathered agent.

Correlation between the Differences between the Two Adjacent Pulse Wave Velocities and Body Mass Index

Correlation between the Differences between the Two Adjacent Pulse Wave Velocities and Body Mass Index

Mechanism of deformation of adjacent rock mass under heat-emitting practices used

Mechanism of deformation of adjacent rock mass under heat-emitting practices used

Effect of soil-rock interface position on seismic response of subway station structure

For subway stations in a site with thin soil layers on the engineering rock, the lower part of the subway station is embedded in the hard rock mass and the upper part is buried in the soil layers. The presence of the soil-rock interface may lead to significant increase to the seismic responses of the adjacent soil masses and underground structures. In this paper, the effect of the soil-rock interface position on the seismic response of a two-story and three-span subway station structure is investigated by numerical analyses. It is found from the numerical analyses that a most detrimental soil-rock interface position exists and makes the underground structure have maximum responses under a given artificial earthquake motion. For the upper floor, the most detrimental soil-rock interface position is near the middle slab. For the lower floor, the most unfavorable soil-rock interface position is near the bottom slab. Softer site generally leads to greater structural responses under the same intensity of ground motion excitation. On the basis of the above findings, three earthquake motions included above an artificial earthquake motion and other two real earthquake motions and three burial depths of structure are further studied. Same conclusions can be obtained for the structure with different burial depths or subjected to different input earthquake motions. The conclusions drawn from the numerical examples of this paper may be useful for seismic design of subway station structure buried in shallow soil layers on rock.

Identification of unstable rock mass areas by vibroseis survey

Rock mass quality governs the choice of parameters for board gates and stopes and their support systems. Even the same lithology rock mass may have varying quality, and the correct rock mass quality assessment is therefore an obligatory condition for validation of engineering solutions. During mineral mining, rock mass behavior is assessed from a limited set of data, and predictive estimates are inaccurate, which leads to the erroneous mine support designs and stoping span parameters. Such errors can be essentially reduced by means of additional measurements performed during drilling. The analysis of vibroseis survey data obtained to determine rockburst hazard categories of rock mass shows a good agreement between measurements and the actual condition of roofs in stopes. Rocks with the lowest values of safety factor (SF) feature the highest stability, and, vice versa, rocks having the higher values of SF show the least stability indices. Stability of enclosing rock mass worsens with time owing to the change in induced jointing caused by stress redistribution in adjacent rock mass, which is also confirmed by the vibroseis measurement data. The authors describe using XML as the measurement data storage for standardized electronic data transition and proper control. The digitalization is possible without additional finance and using standard Microsoft Office utilities.

Inverse eigenvalue problem for mass–spring–inerter systems

This paper has solved the inverse eigenvalue problem for a “fixed–free” mass-chain system with inerters. It is well known that for a spring–mass system wherein the adjacent masses are linked through a spring, the natural frequency assignment can be achieved by choosing appropriate masses and spring stiffnesses if and only if the given positive eigenvalues are distinct. However, when we involve inerters, multiple eigenvalues in the assignment are allowed. In fact, for a set of arbitrarily given positive real numbers, we derive a necessary and sufficient condition on the multiplicities of these numbers, which are assigned as the natural frequencies of the concerned mass–spring–inerter system.

Invasive papillary carcinoma of the breast: a rare case report

BackgroundInvasive Papillary Carcinomas (IPC) are rare and account for approximately 0.5% of all invasive breast carcinomas. Most of them are seen in post-menopausal women and have a good prognosis. These tumors lack the myoepithelial cell layer (MCL) within the papillae or at the periphery of the tumor with areas showing stromal invasion or invasion into lymphovascular spaces. Immunohistochemistry (IHC) for myoepithelial cells and basement membrane is essential for the diagnosis of invasive cancer.Case presentationWe present a rare case of IPC in a 74-year-old woman who presented with complaints of gradually increasing painless retroaerolar mass in the left breast of two months duration. The mass was irregular, having an oblong as well an adjacent high density mass lesion on mammography. Ultrasound (US), and Magnetic Resonance Imaging (MRI) helped in the diagnosis of the possibility of a malignant breast lesion. Left-sided modified radical mastectomy was performed and the specimen was histopathologically diagnosed as Invasive Papillary carcinoma. Immunohistochemistry confirmed the diagnosis.ConclusionsInvasive Papillary Carcinomas of the breast are rare cancers in post-menopausal women. We have highlighted the role of Mammography, US, and MRI in early diagnosis so that timely management is possible.

PORCELAIN PLEURA: A RARE CASE OF METASTATIC CHONDROSARCOMA WITH EXTENSIVE PLEURAL CALCIFICATION

TOPIC: Disorders of the Pleura TYPE: Fellow Case Reports INTRODUCTION: Calcified pleural lesions have both benign and malignant etiologies. Benign lesions can originate from previous trauma, prior pleural infections, hemothorax, or asbestos exposures, and are often focal and limited1,2. Malignant lesions often involve metastatic disease from mesenchymal tumor origin, such as osteosarcoma, chondrosarcoma, or mesothelioma1,3. We describe a case of a patient with metastatic chondrosarcoma manifesting with extensive calcification of the parietal and visceral pleura. CASE PRESENTATION: A 67 year old man was referred to pulmonary for a new subcarinal soft tissue mass on chest CT. He had been previously diagnosed with chondrosarcoma in 2016 and underwent treatment via a radical right proximal humerus excision and shoulder arthroplasty, with final pathology revealing grade 2 conventional chondrosarcoma, mixed hyaline and myxoid, without metastatic foci.Screening chest CT in 2020 noted a new, partially calcified subcarinal soft tissue mass and adjacent lymphadenopathy with moderate hypermetabolism on a positron emission tomography scan (PET/CT). Bronchoscopy with endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) subcarinal lymph node and adjacent posterior mass confirmed metastatic disease.He subsequently developed rapidly progressive dyspnea on exertion over the following month. Repeat chest CT revealed extensive development of circumferential nodularity and calcification of the right visceral and parietal pleura with a large pleural effusion. Thoracentesis improved dyspnea despite limited reexpansion of the lung and noted loculation of the effusion. Pleuroscopic evaluation of the complicated space was undertaken to remove loculations and optimize placement of an indwelling pleural catheter (IPC) for his malignant effusion. Despite difficulty with trocar insertion into the calcified pleural space, placement of the IPC was successful with improvement in his dyspnea. DISCUSSION: Metastatic pleural involvement of chondrosarcoma is rare, and can occur in the setting of direct extension in locoregional disease or hematogenous spread from other sites of primary involvement. Metastatic disease has been noted to be more prevalent in the dedifferentiated and mesenchymal subtypes4. Manifestations of metastatic pleural involvement are typically pleural calcifications that can be profound in the rapid evolution and extent of calcified involvement. Management is often palliative, as in this case, with drainage of any associated pleural effusions and attempts to mitigate accompanying dyspnea. CONCLUSIONS: This case of metastatic chondrosarcoma with extensive visceral and parietal pleural involvement is rare and infrequently noted in the literature. Palliative management with thoracentesis and IPC placement was complicated by the pervasive pleural calcification that prevented ultrasound imaging and made access to the pleural space difficult and dangerous. REFERENCE #1: Sureka B, Thukral BB, Mittal MK, Mittal A, Sinha M. Radiological review of pleural tumors. Indian J Radiol Imaging. 2013;23(4):313-320 DISCLOSURES: No relevant relationships by Robert Browning, source=Web Response, value=Grant/Research Support Removed 04/29/2021 by Robert Browning, source=Web Response No relevant relationships by Robert Browning, source=Web Response, value=Consulting fee Removed 04/29/2021 by Robert Browning, source=Web Response No relevant relationships by Robert Browning, source=Web Response, value=Consulting fee Removed 04/29/2021 by Robert Browning, source=Web Response No relevant relationships by Sean McKay, source=Web Response No relevant relationships by Philip Mullenix, source=Web Response No relevant relationships by Caitlin Nickens, source=Web Response No relevant relationships by John Shumar, source=Web Response

Technical and technological aspects of the coal mine closure based on the geomechanical component assessment

Purpose.Development of a comprehensive methodology for assessing the state of mine workings based on the analysis of their contour displacement patterns when solving the problem of minimizing the risks during the closure of coal mines in Ukraine. Methods. Based on an integrated analysis of international and domestic trends when assessing the consequences of mine closure, the main provisions of using the method of instrumental mine observations have been substantiated. When solving the problem, the approaches of regulatory documents are taken into account to identify the geomechanical situation according to two conditions: the structure and strength properties of the lithotypes in the adjacent coal-bearing stratum and the peculiarities of the rheological processes manifestation during the development of its displacements. Findings. The geomechanical, technological and hydrogeological factors have been distinguished that are required to take into account when closing the coal mines. Fundamental methodological provisions have been substantiated for the most reliable assessment of the mine workings state, taking into account the long period of their operation. A criterion for making a decision on the decommissioning of mine workings or their further maintenance is presented. Originality.A series of generalizing dependences of the mine working contour displacement development has been obtained, which can be divided into four main groups according to the criteria of the structural and strength properties of lithotypes in the adjacent mass, as well as the type of their rheological manifestations: decaying and persistent deformation creep. For each group, using the methods of correlation-dispersive analysis, empirical formulas have been determined for calculating the convergence of the roof and bottom of mine workings, as well as their sides, depending on the geomechanical criterion H/R of the maintenance conditions and the duration t of this period. Practical implications.The obtained correlation ratios make it possible to predict the residual section of mine working at any time of its maintenance. They are a geomechanical component of its operational state assessment. The result of this research is the development of a new methodology for assessing the mine working state according to the patterns for predicting its contour displacement.

Development of multi-band tuned rail damper for rail vibration control

The intense interaction force between the wheel-rail causes the vibration of wheel and rail, and generates rolling noise. Increasing the rail damper is an effective way to suppress rail vibration. In this paper, a shear-type multi-band tuned rail damper (MTRD) consist of internal mass bars and external resilient layer to reduce rail vibration is proposed. Mass bars are wrapped inside resilient layer and placed along the length of rail. Resilient layer between two adjacent mass bars can enforce them perform shearing motion corresponding to the layer along the main vibration direction of rail. Different oscillation frequencies corresponding to different mass bars can be tuned by adjusting the structure of MTRD. It achieves an increase in the operating frequency band and a widening of the operating frequency range of MTRD. The influence of parameters of MTRD on its performance is investigated by the finite element method (FEM). One of three designed MTRD models is selected for prototype production after comparative analysis. Laboratory measurements are conducted on a rail specimen and 12 m track platform. Results show the main operating frequency band of designed MTRD is in the range of 200 Hz–800 Hz, achieves the goal of the desired frequency band. Frequency response function tests of rail on 12 m platform show the MTRD could suppress rail vibration in the range of 100–2000 Hz. To estimate the practical reduction effects of MTRD on vibration, a small radius curve of metro line is selected for field measurements. The measured track decay rate (DR) shows MTRD could increase DR at frequencies above 80 Hz with a max increment of 5 dB/m and 9.3 dB/m in vertical and lateral direction respectively. Reduction of rail vibration and rolling noise when trains pass is also measured. The overall vibration level of rail achieves a max reduction of 10.9 dB and 6.3 dB in vertical and lateral directions respectively. The overall sound pressure level is reduced by 5.9 dB(A) at the speed of 60 km/h.

Effect of the anchors' free length that made of tubular screw rods on the forces distribution in pile-anchor retaining structures on highways

Pile-supported retaining structures are widely used to protect road sections from landslide processes. The article describes the design and calculation peculiarities of pile-supported retaining structures reinforced with a drill and inject anchors from tubular screw rods. The authors considered two options for this type of anchors setup: without free length and with a pre-set free length. In the software geotechnical complex Plaxis, on the finite element method basis, mathematical modeling and calculation of a pile-supported anchor retaining structure with different free anchors lengths from tubular screw rods for various soils types have been performed. Numerical relationships have been obtained between the anchors' free length and the resulting forces in the retaining structure. The performed calculations series of the test scheme showed that with an increase in the free anchors' length in the retaining structure, there is a decrease in the applied load in its load-bearing elements due to the horizontal displacements growth. The article presents the survey results of a real road section, on which a landslide displacement is being prepared, and considers a design solution for a pile-supported anchor retaining structure to ensure its safe operation. Performed a series of calculations for various landslide process development stages in this area showed that the effect of the anchors' free length also largely depends on the state of the adjacent soil mass. Obtained results clearly show that the design of a free length section for anchors made of tubular screw rods makes it possible to design more cost-effective pile-supported anchor holding structures without reducing their reliability.

MODERN METHODS OF GROUND-BASED INTERFEROMETRY IN MONITORING ADJACENT ROCK MASSES IN OPEN PIT MINING

This article analyzes modern monitoring methods using ground-based interferometric radars. Currently, there are only a few companies on the world market that offer interferometric scanning solutions. These are IDS (Italy), part of the Hexagon group, Groundprobe (Australia), Reutech (South Africa) and the very rare LISA (JRC-Lisalab) and GPRI (Gamma Remote Sensing). Such radars can be used in the open pit mine development of mineral resources for monitoring the safety of adjacent rock masses, dumps and dams. The article considers the general principle of interferometric radars’ operation and differences between them. It also describes different types of aerials, which are being used nowadays in ground-based interferometric scanning. The analysis results enabled to formulate the recommendations for using different type radars depending on the strategy of geotechnical monitoring.

Simulating observed cloud transitions in the northeast Pacific during CSET

AbstractThe goal of this study is to challenge a large eddy simulation model with a range of observations from a modern field campaign and to develop case studies useful to other modelers. The 2015 Cloud System Evolution in the Trades (CSET) field campaign provided a wealth of in situ and remote sensing observations of subtropical cloud transitions in the summertime Northeast Pacific. Two Lagrangian case studies based on these observations are used to validate the thermodynamic, radiative and microphysical properties of large eddy simulations (LES) of the stratocumulus to cumulus transition. The two cases contrast a relatively fast cloud transition in a clean, initially well-mixed boundary layer vs. a slower transition in an initially decoupled boundary layer with higher aerosol concentrations and stronger mean subsidence. For each case, simulations of two neighboring trajectories sample mesoscale variability and the coherence of the transition in adjacent air masses. In both cases, LES broadly reproduce satellite and aircraft observations of the transition. Simulations of the first case match observations more closely than for the second case, where simulations underestimate cloud cover early in the simulations and overestimate cloud top height later. For the first case, simulated cloud fraction and liquid water path increase if a larger cloud droplet number concentration is prescribed. In the second case, precipitation onset and inversion cloud breakup occurs earlier when the LES domain is chosen large enough to support strong mesoscale organization.

A method for calculating loads on roof support in mines

The author proposes an approach to the stress–strain analysis of mine support with regard to all displacements of the stope boundary until it makes contact with the support using the stiffness matrix of intact rock mass. Modeling of the void formation and of the joint deformation of the support and adjacent rock mass uses iterative procedures from the methods of initial stresses and initial strains. The support load algorithm and software package are developed.

Impact of blasting on pit wall rock mass

The paper presents the research findings obtained by the Institute of Mining in drilling and blasting in Dzhetygara open pit mass. The research was aimed at enhanced stability of stationary benches and at cost minimization of drilling and blasting. The research met two objectives. First, in terms of Dzhetygara deposit, perimeter blasting designs were developed, which ensured reduced impact of blasting on adjacent rock mass. Second, the blast-induced PPV measurement procedure was refined and introduced, and the blasting technology was improved for blasting operations at ultimate pit limit. The special technology for ultimate pit perimeter blasting includes: analysis of blast effects on pit wall rock mass; finding of mechanisms of wave processes in rock mass; interaction of perimeter blasts depending on strength characteristics of rock mass; field trial of cutback methods; determination of sequence of blasts when approaching a guarded sites; determination of efficiency criteria of drilling and blasting.

Lymphoepithelial cyst mimicking pancreatic cancer: a case report and literature review

BackgroundPancreatic lymphoepithelial cyst (LEC) is a rare nonmalignant cyst consisting of a benign collection of keratinizing squamous epithelial cells with lymphoid tissue. Diagnosing LEC preoperatively is considered difficult because of its non-specific clinical features; therefore, LEC is generally treated the same as a malignant tumor.Case presentationOur case was a 65-year-old man who underwent pancreatoduodenectomy 3 years previously for carcinoma arising from the ampulla of Vater. A pancreatic mass in the remnant pancreatic tail was detected through follow-up abdominal contrast-enhanced computed tomography (CT). This revealed two adjacent ring-enhanced masses that had been in tight contact with the left diaphragm and were enlarged. The tumors had high signal intensity in diffusion-weighted images of magnetic resonance imaging, and fluorodeoxyglucose-positron emission tomography (FDG-PET) showed abnormal uptake (standardized uptake value maximum: 17.4). Therefore, we conducted a partial resection of the remnant pancreas with concomitant resection of the left diaphragm. Microscopically, one of the tumors revealed rare fragments of apparently benign squamous epithelium on a background of keratinous debris, cyst contents, and scattered lymphocytes, and the adjacent mass revealed infiltrated neutrophils. The histopathological diagnosis was an LEC with chronic abscess. The patient recovered uneventfully and was discharged on postoperative day 10.ConclusionsWe reported a rare case of LEC with chronic abscess that was positively visualized on FDG-PET. When a pancreatic malignancy cannot be excluded, surgical resection is considered inevitable.