Stability Of Drift Research Articles

Thin-Film Transistor Digital Microfluidics Circuit Design with Capacitance-Based Droplet Sensing.

With the continuous expansion of pixel arrays in digital microfluidics (DMF) chips, precise droplet control has emerged as a critical issue requiring detailed consideration. This paper proposes a novel capacitance-based droplet sensing system for thin-film transistor DMF. The proposed circuit features a distinctive inner and outer dual-pixel electrode structure, integrating droplet driving and sensing functionalities. Discharge occurs exclusively at the inner electrode during droplet sensing, effectively addressing droplet perturbation in existing sensing circuits. The circuit employs a novel fan-shaped structure of thin-film transistors. Simulation results show that it can provide a 48 V pixel voltage and demonstrate a sensing voltage difference of over 10 V between deionized water and silicone oil, illustrating its proficiency in droplet driving and accurate sensing. The stability of threshold voltage drift and temperature was also verified for the circuit. The design is tailored for integration into active matrix electrowetting-on-dielectric (AM-EWOD) chips, offering a novel approach to achieve precise closed-loop control of droplets.

ASSESSMENT OF THE STABILITY OF MINE HAULAGE DRIFT USING STATISTICAL ANALYSIS OF ARCH YIELDING SUPPORT FAILURE

Purpose. The stability of mine haulage drift has been evaluated using statistical analysis of arch yielding support failure under different protective measures to create safe working conditions for miners in deep coal mines with steeply dipping seams. Methods. A comprehensive approach was used, including a mine experiment , probability theory methods, and statistical analysis of experimental data. Results. The stability of mine haulage drift on steep seams was assessed in natural conditions under different protective measures. It was found that while using post-and-lintel support to protect the drift, with an arch yielding support failure frequency of w≥0.56 and normal distribution of single-factor dispersion analysis statistics, the loss of cross-sectional area of the excavation over the length of the mining site was about 50%. While using cribbing support for protection, with an arch yielding support failure frequency of w≥0.29, the loss of cross-sectional area was 30%. Empirical frequency w of the arch yielding support failure along the length of the excavation does not differ from theoretical frequencies, allowing the probability of an event related to deterioration of the stability of the mine haulage drift along the length of the mining site to be determined within a confidence interval under different protective measures. Novelty. A functional dependence was established to evaluate the stability of the mine haulage drift under different protective measures along the length of the mining site using single-factor dispersion analysis statistics of arch yielding support failure. Practical significance. Based on the statistical analysis of arch yielding support failure installed in the mine haulage drift, it is advisable to consider that the operational condition of the preparatory workings is ensured when using protective structures in the form of wooden cribbing support.

Study on Calibration of Chromlum(VI) Analyzer

This article presents a novel metrological calibration method for trace chromium(VI) analyzer. The study identifies all factors that affect the accuracy of chromium(VI) analyzers, and proposes calibration items and method for the analyzer based on its working principle. The calibration items include pump set flow error and pump flow stability, set temperature error and temperature control stability of column oven, baseline noise and drift, minimum detection concentration, linear range, and qualitative and quantitative repeatability. Experimental results shows that, the presented method can meet the requirements for the metrological performance evaluation of chromium(VI) analyzer. The calibration method is scientific and feasible.

Ground calibration of the Mars orbiter magnetometer onboard Tianwen-1

Ground calibration experiments of the Mars orbiter magnetometer (MOMAG) onboard the orbiter of Tianwen-1 were performed to determine the sensitivity, misalignment angle, and offset of the sensors. The linearity of the applied calibrated magnetic fields and the output from the sensors were confirmed to be better than 10⁻⁴, and the sensor axes were orthogonal to each other within 0.5 degrees. The temperature dependencies of the sensitivity and misalignment angle were examined, but no clear signatures of temperature dependencies could be seen. Sensor offset and the stability of sensor offset drift with a temperature change were also determined by the rotation method. The stability of the sensor offset drift was less than 0.01 nT/°C. The ground calibration of MOMAG determines all the calibration parameters of the sensors for accurate magnetic field measurements in orbit with the appropriate corrections.

Determination of the Required Strength of Artificial Roof for the Underhand Cut-and-Fill Mine Using Field Measurements and Theoretical Analysis

For the underhand cut-and-fill mining method, to ensure safe and economic mining, a key issue is to correctly determine the required strength of the artificial roof made of cemented paste backfill (CPB). However, the determination of the required strength is typically based on historical experience and analytical beam formulas, resulting in the obtained required strength being unsuitable for the actual situation. Therefore, in order to determine the required strength of the CPB roof reasonably and accurately, field measurements based on sensors were proposed and carried out in the Jinchuan mine, and then formulas based on thick plate theory were derived to verify the measured results. The results show that the required strength obtained by field measurement is 0.325 MPa and that obtained by thick plate theory is 0.304 MPa, with an error of 6.78% between them, verifying the accuracy of the measurements. However, the strength standard currently used by Jinchuan is 0.59 MPa, which far exceeds the optimal strength and results in many additional, unnecessary expenses. To ensure economical mining, the span of the drift was enlarged from 5.0 m to 6.0 m based on the results of the actual measurements and the current production status of the mine. The measurements show that the maximum cumulative subsidence of the drift roof is 11.69 mm and the maximum convergence deformation of the sidewalls is 8.34 mm, which indicates that the stability of the span-enlarged drift is satisfactory. Meanwhile, enlarging the drift span allows for a 20% increase in production capacity per mining cycle. This field measurement method and theoretical analysis model can be used as an efficient guide to facilitate the design of underhand cut-and-fill mining.

Effect of spatial variability of creep rock on the stability of a deep double-lined drift

This work aims at investigating the effect of aleatoric uncertainty of creep rock properties on the stability of an underground structure. This uncertainty relates to the spatial variability of the mechanical parameters representing the time-dependent behavior of geological rock formation due to the change in its mineralogy. The chosen methodology consists of representing the aleatoric uncertainty of rock properties by random fields, written as correlation functions with respect to the spatial correlation length. The adaptation of the well-known Expansion Optimal Linear Estimationmethod (EOLE) is performed to account for the cross-correlation of the random fields of the viscoplastic parameters of the host rock. Then, the Kriging-based reliability analysis is undertaken with respect to the discretized random fields, which allows elucidating the effect of spatial variability. As an application, the proposed approach is chosen to study the stability in the long-term of a deep double-lined drift within the geological disposal facilities (Cigeo project) conducted by the French National Radioactive Waste Management Agency (Andra). The drift will be excavated in Callovo-Oxfordian (COx) claystone (if the Cigeo project is licensed), considered as a potential host rock for the deep geological nuclear waste disposal in France. The results show that the chosen Kriging metamodel for the reliability analysis can be appropriate for the case of high correlation length represented by a moderate number of random variables (up to about 50) after the discretization of random fields. Further, the consideration of aleatoric uncertainty exhibits a lower probability of exceedance in comparison with the case where spatial variability is ignored. Still, more investigations need to be conducted in the future to conclude this observation.

Performance of open-path lasers and Fourier transform infrared spectroscopic systems in agriculture emissions research

Abstract. The accumulation of gases into our atmosphere is a growing global concern that requires considerable quantification of the emission rates to mitigate the accumulation of gases in the atmosphere, especially the greenhouse gases (GHGs). In agriculture there are many sources of GHGs that require attention in order to develop practical mitigation strategies. Measuring these GHG sources often relies on highly technical instrumentation originally designed for applications outside of the emissions research in agriculture. Although the open-path laser (OPL) and open-path Fourier transform infrared (OP-FTIR) spectroscopic techniques are used in agricultural research currently, insight into their contributing error to emissions research has not been the focus of these studies. The objective of this study was to assess the applicability and performance (accuracy and precision) of OPL and OP-FTIR spectroscopic techniques for measuring gas mole fractions from agricultural sources. We measured the mole fractions of trace gases methane (CH4), nitrous oxide (N2O), and ammonia (NH3), downwind of point and area sources with a known release rate. The mole fractions measured by OP-FTIR and OPL were also input into models of atmospheric dispersion (WindTrax) allowing the calculation of fluxes. Trace gas release recoveries with WindTrax were examined by comparing the ratio of estimated and known fluxes. The OP-FTIR provided the best performance regarding stability of drift in stable conditions. The CH4 OPL accurately detected the low background (free-air) level of CH4; however, the NH3 OPL was unable to detect the background values <10 ppbv. The dispersion modelling using WindTrax coupled with open-path measurements can be a useful tool to calculate trace gas fluxes from the well-defined source area.

СТРУКТУРУВАННЯ ЕКСПЕРИМЕНТАЛЬНИХ ДАНИХ ПРАЦЕЗДАТНОСТІ АРКОВОГО КРІПЛЕННЯ ДЛЯ ІМОВІРНІСНОЇ ОЦІНКИ СТАНУ ВІДКАТНИХ ШТРЕКІВ

Purpose. Structuring of experimental data of mine observations of the performance of arched flexible supports to establish a probabilistic assessment of the state of haulage drifts of steep coal seams in the excavation areas of a coal mine. Methods. The methodological basis of the research is an integrated approach, including the analysis and generalization of scientific achievements on the problem under study; mine observations of the state of development workings; analytical calculations using the basic provisions of probability theory, mathematical statistics using differential equations. Results. A probabilistic assessment of the state of the haulage drift under different protection methods, used to predict the stability of section development workings, was obtained from the experimental data of mine observations (observation time t = 4280 hours) of the performance of the arched pliable lining installed in the working along the length of the excavation section. After the sample was formed, the calculation of a statistical assessment of the reliability of the support operation was performed: the indicators of the failure rate λ and the recovery rate μ were established. Dependencies are obtained that allow assessing the state of development workings along the length of the excavation section and in the zone of influence of the stopping operations. It is proved that in the steady mode of operation of the haulage drift, with an increase in the failure rate of the arch support by 5 times, the availability factor, as a function of the reliability and maintainability of the support, changes from 0.9 to 0.5, which leads to a deterioration in time, approximately by 60 %, operational characteristics of the support in the supported development. Novelty. The probabilistic assessment of the loss of stability of the haulage drift along the length of the excavation section is based on the structuring of the data on the performance of arched supports and depends on the method of protection of the working, the intensity of failures of the arched supple support and the frequency of its damage, when in the desired interval of observations when forming the sample, the position of the stopping front is taken into account. Practical relevance. For the reuse of development workings with a store method of preparing steep seams and a descending order of mining floors, a conceptual model is proposed that allows predicting the state of haulage drifts along the length of the excavation area, taking into account the method of protection.

Nanoparticle-enhanced in-line potentiometric ion sensor for point-of-care diagnostics for tropicamide abuse in biological fluid

Point of care (POC), also identified as on-site testing, has evolved as a rapid and accurate technique for drug of abuse screening and analysis. The aim of this work is to detect tropicamide (TPC) abuse in biological fluids; we selected rat plasma as example. We developed a disposal miniaturized, portable, green, and budget-friendly POC solid-state electrochemical sensor based on potentiometric transduction. To attain that, an innovative microfabricated electrode modified with conducting polymer poly(3-octylthiophene) (POT) has been placed on sensitized printed circuit board (PCB). A two-stage optimization process was implemented to develop the fabricated electrode. The first stage of the optimization process depends on screening various ionophores in order to enhance the sensor selectivity towards tropicamide. Copper nanoparticles exhibited the highest selectivity towards TPC. The second stage was utilizing a polymer as an ion-to-electron transducer layer between the copper nanoparticles impregnated ion sensing membrane and the microfabricated solid-contact ion-selective electrode. This polymer was added to boost the stability of the potential drift (1.2 mV/h) due to the hydrophobic behavior of the POT, which precludes the formation of an aqueous layer at the Cu electrode/polymeric membrane interface and improve the limit of detection (1.1 × 10−8 M). Nernstian potentiometric response was accomplished for TPC with a slope of 58.46 ± 0.43 mV/decade and E0 ∼ 189.39 ± 2.12 over the concentration range 1.0 × 10−7 to 1.0 × 10−2 M. The suggested sensor's intrinsic figure of merits include a quick response time (13 ± 2 s) and long life time (45 days). The proposed sensor has been successfully employed in the selective determination of TPC in pharmaceutical formulations, and biological fluids. When the results were compared to those of the official approach, there was no statistically significant difference. The Eco-Scale tool assessed and measured the greenness profile of the established method.

A novel flow and pressure catheter for complete interventional cardiology physiology management

Abstract Ischemia with No Obstructive Coronary Artery (INOCA) in angina patients increases the risk of major cardiac events, with a 1.5x increased mortality rate. There is a link between COVID-19 infection and impairment in the myocardial micro-vasculation which may cause an increase of INOCA patients. Fractional Flow Reserve (FFR), is the standard of care in cardiology but its diagnostic function is only related to Obstructive Coronary Artery disease (or epicardial) and it is ineffective with INOCA. The lack of effective and accurate tools for timely evaluation of coronary impairments creates a clinical unmet need. The PhysioCath catheter was developed within the Eurostars project “FP-Catheter, E!113577” aims to resolve this need a provide an effective tool to interventional cardiologists. The main project outcome is a catheter prototype equipped with a blood flow velocity sensor based on a thermo-convection principle, and a fiber optic pressure sensor (based on Fabry-Perot principle). While the use of Fabry-Perot type of sensor is already standard in the industry, the use of a thermo-convection sensor represents a progress with respect the state of the art. The sensor creates an overheat of 7°C above the physiological blood's temperature (considered as being within the safety limits), and it exchanges thermal power with the blood stream. The power is then measured and converted to velocity by means of a calibration curve. The project encompassed interviews with 14 clinical experts, the summary of the interviews indicated that the preferred form of the device is an over the wire microcatheter, with rapid exchange. Within the project then, it was developed a 3Fr microcatheter, with a rapid exchange section of 24cm. Both pressure sensor and flow velocity sensor were integrated in this embodiment. Finally, the PhysioCath prototype was evaluated in a bench test study. The test setup was composed by an anatomical silicone phantom of the aortic root and the coronaries (Elastrat, Geneva, Switzerland), perfused with a peristaltic pump (Harvard Apparatus, Holliston MA, US). The measurements performed by the flow velocity sensor were compared against and external doppler flow velocity sensor. While the pressure measurement was assessed for stability and presence of drift. The data processing revealed and extreme accuracy in the measurement of flow based indexes like CFR (±6% variability), accuracy of the blood flow velocity measurement (±10%), and extreme stability in the measurement of both pressure and flow velocity. In the second part of the project (that is currently ongoing), it will be studied the performance of the device within an animal setting. In conclusion, the PhysioCath device is a microcatheter integrating bot pressure measurement and blood flow velocity measurement. Its performance is of very high accuracy and stability, that represent a main step ahead with respect the current state of the art, based mainly on thermodilution. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Eureka-Eurostars Test benchMicrocatheter prototype

Kriging-based reliability analysis of the long-term stability of a deep drift constructed in the Callovo-Oxfordian claystone

Abstract Callovo-Oxfordian (COx) claystone has been considered as a potential host rock for geological radioactive waste disposal in France (Cigeo project). During the exploitation phase (100 years), the stability of drifts (e.g. galleries/alveoli) within the disposal is assured by the liner, which includes two layers: concrete arch segment and compressible material. The latter exhibits a significant deformation capacity (about 50%) under low stress (

Synthetic system design method for off-axis stabilized zoom systems with a high zoom ratio.

Stabilized zoom systems possess the advantages such as the simplified system layout, improved system stability, enhanced imaging performance, and a high zoom speed. The complex system design to achieve high performances requires calculations or investigations of the initial system for optimization and improvements, and thus, specific design techniques are pursued. In this study, we propose an automatic optical design scheme of synthetic characteristics for the off-axis stabilized zoom systems, which using focal length variable (FLV) opto-electronic elements and with a high zoom ratio. The study aims at evaluating and synthetically achieving the zooming properties and the image quality balance of entire focus imaging. The multi-element stabilized zoom systems are characterized using the Gaussian brackets expressions and their optimal solution ranges for high zoom ratios are deduced to achieve non-defocusing imaging in specific stroke ranges of FLV elements. Then considering the analytical characterization of the off-axis-induced primary aberrations at multi-conjugate positions, we use a conic surface to deduce the basic expression of the nodal aberration. Thereby the nonlinear global merit function is established with a semi-empirical mathematical model based on nodal aberration theory and nonlinear zoom equation for maintaining the stability of focal length and image plane drift. And the theory of Pareto Optimality is employed in the process of verifying the superiority of the solutions. Finally, a series of solutions for a high zoom ratio and aberration compensation are implemented and the optimal configurations with conical surfaces for an off-axis stabilized zoom system are obtained.

Stability of Deep Underground Mine Drift through Complex Geology Conditions in Quang Ninh Coal Area

The stability of deep underground mine drifts is pivotal to sustainable, safe mining in underground coal mines. The main objective of this research is to determine the stability and drifting safety issues in 500-m-deep deep underground mine drift through complex geology in the Quang Ninh coal area. The laboratory experimentation and field measurements were used to analyze the large deformations and failure characteristics of the surrounding rock, the influence factors of safe excavation and stability of deep underground mine drift, and to study the stability control countermeasures. This study also shows the main factors influencing the stability and drifting safety include complex geology zones, high in situ stress, poor mechanical properties and engineering performance of the argillaceous rock mass. According to the field study, the groutability of cement-matrix materials in the argillaceous rock in the complex geology zones were extremely poor, and deformations and failure of the surrounding rock were characterized by dramatic initial deformation, high long-term creep rate, obviously asymmetric deformations and failure, the rebound of roof displacements, overall loosened deformations of deep surrounding rock on a large scale, and high sensitivity to engineering disturbance and water immersion. Various geo-hazards occurred during the underground mine drift excavation, including roof collapse, groundwater inrush. Control techniques are proposed and should be adopted to ensure drifting safety and to control the stability of deep underground mine drift through complex geology zones, including choice of reasonable drift shape, reasonable support type, steel sets, regional strata reinforcement technique such as ground surface pre-grouting, primary enhanced control measures, grouting reinforcement technique, and secondary enclosed support measures for long-term stability, which are critical for ensuring the sustainable development of the underground coal mine.

Point-of-care diagnostics for drugs of abuse in biological fluids: application of amicrofabricated disposable copper potentiometric sensor.

The major objective of this work was to develop a portable, disposable, cost-effective, and reliable POC solid-state electrochemical sensor based on potentiometric transduction to detect benzodiazepine abuse, mainly diazepam (DZP), in biological fluids. To achieve that, microfabricated Cu electrodes on aprinted circuit board modified with the conducting polymer poly(3-octylthiophene) (POT) have been employed as a substrate. This polymer was introduced to enhance the stability of the potential drift (0.9mV/h) and improve the limit of detection (0.126nmolmL-1). Nernstian potentiometric response was achieved for DZP over the concentration range 1.0 × 10-2 to 5.0 × 10-7molL-1 with a slope of 55.0 ± 0.4mV/decade and E0 ~ 478.9 ± 0.9. Intrinsic merits of the proposed sensor include rapid response time (11± 2s) and long life time (3months). In order to enhance the selectivity of the potentiometric sensor towards the target drug and minimize any false positive results, calix[4]arene (CX4) was impregnated as an ionophore within the PVC plastic ion-sensing membrane. The performance of the POC sensors was assessed using electrochemical methods of analysis and electrochemical impedance spectroscopy as a surface characterization tool. The studied sensors were applied tothe potentiometric determination of DZP in different biological fluids (plasma, urine, saliva, and human milk) in the presence of its metabolite with an average recovery of100.9± 1.3%, 99.4 ± 1.0%, 101.8 ± 1.2%, and 99.0 ± 2.0%, respectively. Graphical abstract.

Обоснование условий устойчивости откаточных штреков в глубоких шахтах

Purpose. The purpose of the study is to justify the conditions of stability and features of manifestations of rock pressure on the circuit of local preparatory workings with different methods of protection in deep mines.Research Methods. An integrated approach is used, including analysis and generalization of theoretical and experimental studies on the problem of the stability of excavation preparatory workings, with different methods of protection, in mines developing steeply and steeply bedded layers at great depths.Results. As a result of the experimental and analytical studies, it was found that when guarding haulage drifts by compliant security structures (rolling fires from wooden sleepers), the load on the lining of the preparatory mine over time, as the lava moves, tends to a finite value in hyperbolic dependence. In this case, there is a change in its growth, and the displacements of the lateral rocks on the contour of the recoil drift take the greatest values in the initial period of time after coal extraction. However, when protecting the production by fragile security structures, the pillars of coal, a change in the load growth on the lining per unit time occurs according to a linear law, which leads to a deterioration in the stability of the recoil drift behind the face, associated with the loss of the bearing capacity of the lining, designed to support the preparatory development.Scientific novelty. The stability conditions of the recoil drift are based on the representation of the lining installed in the excavation excavation, in the form of a geometrically unchanged system, individual elements of which experience bending deformations from the action of external forces that appear when unloading the coal-bearing massif as a result of mining operations.Practical significance. To improve the safety of miners in deep mines, it is necessary to use compliant structures or laying out worked out space to protect recoil drifts, based on increasing their stability, which ensures their operational state behind the face.

A refined understanding of compressibility effects on the stability of drift ballooning modes

A study is conducted on the impact of plasma compressibility on the stability of drift ballooning modes. The two-fluid and four-field model developed by Hazeltine et al. [Phys. Fluids 28, 2466 (1985)] is employed in this study. Results of linear numerical simulations show that finite compressibility destabilizes ballooning modes which are otherwise stable due to the ion diamagnetic drift effect. A systematic study reveals that the parallel compressibility originating from the two-fluid effect, rather than the drift-acoustic wave coupling suggested by Hastie et al. [Phys. Plasmas 10, 4405 (2003)], plays the most important role in destabilizing the ballooning modes. An analytic evaluation of the dispersion relation underpins the strong sensitivity of this parallel compressibility term in the ballooning mode stability. The potential impact of this new understanding on the physics of small edge localized modes is discussed.

Current genetic status, temporal stability and structure of the remnant wild European flat oyster populations: conservation and restoring implications

The flat oyster (Ostrea edulis) is one of the most appreciated molluscs in Europe, but natural beds have been greatly reduced due to harvesting and the effects of the parasite Bonamia ostreae. Characterization of current wild populations is required to develop long-term bed restoration programmes by enhancing genetic diversity and tolerance to bonamiosis. Oysters from different locations corresponding to the main natural beds from Denmark, The Netherlands, England, Ireland, France and Spain, including two different cohorts per location were sampled in 2011 and 2013. Sixteen microsatellite loci were used to study temporal and geographical genetic structure. Temporal variation was low, although sometimes significant probably due to high variance in reproductive success among individuals. Conversely, samples from different countries showed much higher genetic divergence, and Ireland and France presented differences among locations within country. Clustering analyses grouped samples into three main geographical regions, associated with oceanic fronts: one group constituted by The Netherlands and Denmark; another by France, Ireland and England; and a third one exclusively by Spain. Effective population sizes (Ne) within regions were high (>1000), which reflects population stability and low levels of genetic drift. The presence of regional genetic structure shows the potential for local adaptation of O. edulis and suggests caution when transplanting individuals, especially between distant geographical regions.

Development of a low-drift integrator system on the HL-2A tokamak.

In this work, we developed a new integrator system with low-drift and small integration time constant less than 1 ms, which applies to the weak signals from magnetic measurements. This integrator system is designed on the basis of the analog drift compensation and the real-time digital correction of residual drift. The analog drift compensation is achieved by the subtraction between two integrators and the digital correction method is available due to the stability of integral drift in short time scale. The algorithm of the residual drift calculation and correction is implemented by the field programmable gate array. The integral drift can be well compensated within 10 mV/10 s at RC = 0.5 ms and meet the requirements of magnetic diagnostic on HL-2A.

On the characteristics and potential facilities of the sensitive unit of the GT-2A gravimeter

Characteristics of the sensitive unit of the aerogravimetric complex GT-1A (GT-2A) are examined on the basis of experimental material obtained during aerogravimetric surveys. The stability of the zero-point drift of this sensitive unit, the function of the approximation of zero-point drift, the stability of the initial indications on a particular airdrome reference point and the correspondence between the difference in initial readings at different airports and that of gravitation acceleration values according to the first-order State gravimetric network data are discussed.

PRACTICAL APPLICATION OF STOCHASTIC METHODS IN GEOTECHNICAL ENGINEERING

Mine haulage drifts are the only stope access in sub-level stoping mining system. Thus, they must remain stable during their service life. Haulage drift instability could lead to serious consequences such as: production delay, damage to equipment, loss of reserves and high operational cost. The goal of this paper is the performance stability evaluation of mine haulage drifts with respect to mining sequence adopting different stochastic methods of analysis. A two-dimensional, elastoplastic, finite difference code (FLAC 2D) is used for this study. Stochastic analysis; adopting Point-Estimate Methods (PEMs), Monte-Carlo Simulation (MCS) and Random Monte-Carlo Simulation (RMCS) are then employed with the numerical modelling to tackle the inherent uncertainty associated with rockmass properties. Then, the probability of instability at last mining step (e.g., after excavating stope 3) is estimated for haulage drift side walls and roof. The stability indicators are defined in terms of displacement, stress and the extent of yield zones, which are adopted as a basis for assessing the performance stability of haulage drift. The stochastic results are presented and compared in terms of probability of occurrence at last mining stage (e.g., after excavating stope 3) adopting displacement/convergence criterion.