instantaneous outbursts in underground coal mines an overview and association with coal type instantaneous outbursts in underground coal mines have occurred in at least 16 countries involving both methane ch4 and carbon dioxide co2 the precise mechanisms of an instantaneous outburst are still unresolved but must consider the effects of stress gas content and physico mechanical properties of the coal other factors such as mining methods e g development heading into the coal seam and geological features e g coal seam disruptions from faulting can combine to exacerbate the problem prediction techniques continue to be unreliable and unexpected outburst incidents resulting in fatalities are a major concern for underground coal operations gas content thresholds of 9 m 3 t for ch4 and 6 m 3 t for co2 are used in the sydney basin to indicate outburst prone conditions but are reviewed on an individual mine basis and in mixed as situations data on the sorption behaviour of bowen basin coals from australia have provided an explanation for the conflicting results obtained by coal face desorption indices used for outburst proneness assessment a key factor appears to be different desorption rates displayed by banded coals which is supported by both laboratory and mine site investigations dull coal bands with high fusinite and semifusinite contents tend to display rapid desorption from solid coal for a given pressure drop the opposite is true for bright coal bands with high vitrinite contents and dull coal bands with high inertodetrinite contents consequently when face samples of dull fusinite or semifusinite rich coal of small particle size are taken for desorption testing much gas has already escaped and low readings result the converse applies for samples taken from coal bands with high vitrinite and or inertodetrinite contents in terms of outburst potential it is the bright vitrinite rich and the dull inertodetrinite rich sections of a coal seam that appear to be more outburst prone this is due to the ability of the solid coal to retain gas even after pressure reduction creating a gas content gradient across the coal face sufficient to initiate an outburst once the particle size of the coal is reduced rapid gas desorption can then take place c 1998 elsevier science

monitoring and modelling of gas dynamics in multi level longwall top coal caving of ultra thick coal seams part ii numerical modelling abstract the longwall top coal caving method which enables the most productive exploitation of thick ultra thick coal seams may result in a distinct geomechanical response of strata and associated gas emission patterns around longwall layouts a two way sequential coupling of a geomechanical and a reservoir simulator for the modelling of gas emissions around a longwall top coal caving ltcc panels was developed building on the understanding established from the analysis of in situ gas pressure and concentration measurements carried out at coal mine velenje in slovenia model findings have shown that the modelling method implemented can reproduce the dynamic changes of stresses and gas pressure around a ltcc face and predict the total gas emissions and mixed gas concentrations accurately it was found that in ltcc panels although the rate of gas emission from mined coal depends highly on the coal face advance floor coal and roof goaf act as a constant and steady gas source accounting for a considerable part of the overall gas emission research has shown that at first and or second mining levels of multi level ltcc mining a notable stress relief and pore pressure drop induced by fracturing of the mined and roof coal can be experienced within 40 m ahead of the face line in the floor coal on the other hand the pore pressure change was found to extend to 20 m below the mining horizon model results have clearly shown the permeability enhancement and gas mobilisation zones around the ltcc panel which can be the target zones for gas drainage boreholes

a tensile model for the interpretation of microseismic events near underground openings for small scale microseismic events the source sizes provided by shear models are unrealistically large when compared to visual observations of rock fractures near underground openings a detailed analysis of the energy components in data from a mine by experiment and from some mines showed that there is a depletion of s wave energy for events close to the excavations indicating that tensile cracking is the dominant mechanism in these microseismic events

numerical simulation of microseismicity induced by deep longwall coal mining abstract to find an effective numerical simulation method for microseismicity induced by deep mining activity results obtained by using four simulation methods namely 1 the energy release rate method based on cook s study 2 the strain energy release rate method developed by the authors 3 the volume excess shear stress index method based on spottiswoode s study and 4 the maximum shear seismic moment release rate method developed here by the authors were compared with the microseismicity in a japanese deep longwall coal mine the maximum shear seismic moment release rate method was discovered to be the best method since the intensity of microseismicity in a longwall coal panel its variation with the face advance and the distribution of microseismic events were well simulated

characteristics of stratum movement induced by downward longwall mining activities in middle distance multi seam abstract with the development of mining depth multi seam mining activities is becoming more and more frequent correspondingly the study on stratum movement characteristics induced by multi seam mining activities is of great significance for preventing water inrush disaster and forecasting support pressure surface deformation gas drainage and other mining problems according to the interaction among the caved zone the fractured zone and the continuous deformed zone caused by the multi seam downward mining activities multi seam can be divided into three types i e the short distance middle distance and long distance multi seam this paper carries out a case study on the middle distance multi seam mining activities in a coal mine in china to investigate the characteristics of stratum movement caused by downward longwall coal mining activities in the multi seam by means of borehole water level observation digital borehole camera test microseismic monitoring surface crack observation of the surface cracks and distinct element modelling by analyzing the in site monitoring results and the numerical simulation results it can be found that the failure of the key stratum between the lower and upper seams resulting in the connection between the failed zone in floor induced by the upper seam and the fractured zone induced by the lower seam after the failure of the key stratum the mining activities of the lower seam has a great influence on the secondary stratum movement in the overburden these effects are mainly reflected in the rapid increase of horizontal displacement and vertical displacement which caused the caved and fractured zones extend upward in the overburden and then surface cracks increase significantly the above research results are of great significance for the prevention and control of disasters induced by downward longwall mining activities in middle distance multi seam

palaeoweathering profiles developed on the iberian hercynian basement and their relationship to the oldest tertiary surface in central and western spain

advanced techniques in site characterization and mining hazard detection for the underground coal industry abstract today s highly productive coal mining systems represent large capital investments careful geotechnical planning and design are essential to protect these systems and to help ensure their overall success too often however the ability of the mine operator to adequately characterize the geotechnical environment and keep up with changing geologic conditions lags the advance rate of the mining equipment seismic tomographic imaging based on the same principles as medical computer aided tomography cat scans offers the ability to identify changing geologic conditions loading patterns and the location of nearby abandoned mine workings although seismic tomography has been used for many years in the oil industry until recently its practicality in the mining industry has been limited because the processes involved interfered with mining productivity and were labor intensive in terms of data collection and interpretation new advancements in signal processing have greatly enhanced the speed resolution and range of applications of tomographic imaging in underground coal mine settings many tomography applications in the mining industry use seismic velocity and or attenuation tomography within a volume enclosed by the seismic source and receiver array although results obtained using this geometry work well in many situations recent developments in reflection tomography show promise in eliminating the requirement that the target volume be surrounded by sources receivers for example in seam seismic reflection tomography may now be used to image structures and or old workings from one general location in the mine e g face areas of mains and panel developments well ahead of planned developments largely eliminating the need to probe hole drill on regular intervals these new developments have greatly expanded the ability of the mine operator to cost effectively characterize previously inaccessible areas of the property this paper gives an overview of the theories and processes involved in seismic tomography applicable to coal mine settings recent examples are presented of tomographic imaging applied to a variety of coal mine ground control problems and old works detection in the united states and europe the applicability of both seismic refraction and seismic reflection tomography is discussed

pedogenic and groundwater processes in a closed miocene basin northern spain abstract the sepulveda ayllon basin sab was an episodically closed miocene basin adjacent to the tertiary duero basin northern spain the sediments studied here represent a depositional system developed from the margin to the centre of the basin by alluvial fan mud flat and saline mud flat ephemeral lacustrine environments an assemblage of authigenic lithotypes was formed in the basin their distribution being influenced by that of the depositional environments within the basin authigenesis took place mainly before sedimentation of the next set of beds in the distal alluuial fan authigenesis of smectite outer part palygorskite inner part and calcrete predominates and the original muddy deposits are still recognizable in the mud flat a more intense transformation of the sediments took place with predominant formation of palygorskite outer part interstitial gypsum calcrete outer part dolocrete inner part and brown silcrete in the saline mud flat ephemeral lake original sediment was extensively disturbed and replaced by magnesian clays sepiolite and magnesian smectite interstitial gypsum dolocrete and cream and white silcrete authigenic alteration within each cycle varied in time and place and was both pedogenic and groundwater related the authigenic assemblages point to a closed basin under evaporation in a seasonally dry climate at the end of this period the sab became connected with the duero basin to the northeast thus losing the endoreic regime consequently the authigenic evaporitic assemblages were then unstable and were partially replaced by a late sparry calcrete

prediction of coal face rockbursts and microseismicity in deep longwall coal mining a new method is proposed for predicting rockbursts as well as microseismicity in deep longwall coal mining the method is able to predict failure in the coal seam and in the rock mass by using 3 d elastic numerical stress analyses these locations were compared with the results of microseismic monitoring fracturing intensity and its variation with respect to face advance were represented by the maximum shear seismic moment release rate the seismic moment method was applied to three cases in the horonai coal mine and in the miike coal mine japan the first case considered panels w8 5u and ws 5 in the horonai coal mine at 1055 and 1125m deep even though no rockburst occurred areas where microseismic events were concentrated were predicted it was also clear by comparing calculated maximum shear seismic moment release rate to observed data that the magnitude of the seismicity and its variation with respect to the face advance were also successfully predicted the second case corresponded to panel w6 3 in the same mine from 915 to 985m deep microseismic monitoring had not yet been introduced however the rockburst in this panel was successfully predicted as fracturing of coal seam elements at the coal face the last case considered panels e3 e6 in the miike coal mine at 600 and 650 m deep respectively the location and intensity of microseismicity were again predicted in addition toppling as well as rockbursts were also predicted relations between the extent of the relief zone ahead of the coal face and the occurrence of rockbursts are discussed an effective method to prevent rockburst hazard is also proposed

seismic measurements for safety in mines the study of rock stresses and their changes is of great importance for safety in mines to detect dangerous stress accumulations in coal mines an empirical method jahn s drilling test is generally used an experimental survey to solve the same problem by geophysical measurements was undertaken in a hungarian coal mine the basic idea was to determine the easily measurable seismic velocities instead of the more difficult to measure stresses in the rocks since there is a monotonic relation between them during the survey seismic transmission type measurements were carried out in the fore field of longwall faces between the top and tail roads the seismic velocity data obtained were processed using an iterative algebraic reconstruction technique to determine the velocity field i e the seismic velocity distribution of the area covered by the ray paths by periodically repeating the measurements in the same area it was possible to follow the changes in the stress conditions caused by mining operations

naturally occurring arsenic in groundwater and identification of the geochemical sources in the duero cenozoic basin spain arsenic concentrations surpassing potability limit of 10 g l in the groundwater supplies of an extensive area in the duero cenozoic basin central spain have been detected and the main sources of arsenic identified arsenic in 514 samples of groundwater having mean values of 40 8 g l is natural in origin geochemical analysis of 553 rock samples assaying arsenic mean values of 23 mg kg was performed spatial coincidence between the arsenic anomaly in groundwater and the arsenic lithogeochemical distribution recorded in the middle miocene clayey organic rich zaratan facies illustrates that the rocks of this unit are the main source of arsenic in groundwater the ferricretes associated to the late cretaceous middle miocene siliciclastics also constitute a potential arsenic source mineralogical study has identified the presence of arsenic in iron oxides authigenic pyrite manganese oxides inherited titanium iron oxides phyllosilicates and organomineral compounds arsenic mobilization to groundwater corresponds to arsenic desorption from iron and manganese oxides and from organic matter

geological and geochemical examination of arsenic contamination in groundwater in the holocene terai basin nepal geological and geochemical study has been carried out to investigate arsenic contamination in groundwater in nawalparasi the western terai district of nepal the work carried out includes analyses of core sediments provenance study by rare earth elements analyses 14c dating and water analyses results showed that distribution of the major and trace elements are not homogeneous in different grain size sediments geochemical characteristics and sediment assemblages of the arsenic contaminated nawalparasi and uncontaminated bhairahawa area have been compared geochemical compositions of sediments from both the areas are similar however water chemistry and sedimentary facies vary significantly extraction test of sediment samples showed significant leaching of arsenic and iron chemical reduction and contribution from organic matter could be a plausible explanation for the arsenic release in groundwater from the terai sediments

coal and gas outbursts in footwalls of reverse faults abstract instantaneous outbursts in coal mines involve catastrophic and forceful expulsion of coal and large quantities of gas creating a major mining hazard other researchers have studied relationships between coal outbursts and many geological factors such as coal seam thickness coal rank coal seam age current burial depth and distance to plutons with different conclusions for different coal fields and regions because of the complexity of the causative mechanisms coal outbursts nearly always have a close relationship to geologic structures the present research was designed to determine the location and characteristics of specific danger zones associated with reverse faults four coal mines in the pingdingshan coal field henan province china were investigated in detail coal and gas outbursts associated with reverse faults nearly always occurred in the footwalls additional data were also used from two mines in sichuan province and one in henan province the first important observation of the geological structural phenomena was that coal seams in the footwalls of the reverse faults underwent greater tectonic deformation than those in the hanging walls coal lost its banded character and was physically transformed into microstructurally altered forms categorized as cataclastic coal granular coal and mylonitic coal outbursts always occurred within a zone of this tectonically altered coal surrounding the fault second the zone of tectonic alteration in the footwalls extended farther from the fault than that in the hanging walls third where present in association with reverse faults zones of higher coalbed methane content nearly always occurred in the footwalls these three factors are the principal controls on coal and gas outbursts associated with reverse faults through their application coal safety experts can narrow the predicted outburst danger zone to a smaller area

coalbed methane from hazard to resource abstract coalbed gas which mainly consists of methane has remained a major hazard affecting safety and productivity in underground coal mines for more than 100 years coalbed gas emissions have resulted in outbursts and explosions where ignited by open lights smoking or improper use of black blasting powder and machinery operations investigations of coal gas outbursts and explosions during the past century were aimed at predicting and preventing this mine hazard during this time gas emissions were diluted with ventilation by airways e g tunnels vertical and horizontal drillholes shafts and by drainage boreholes the 1970 s energy crisis led to studies of the feasibility of producing the gas for commercial use subsequent research on the origin accumulation distribution availability and recoverability has been pursued vigorously during the past two decades since the 1970 s research investigations on the causes and effects of coal mine outbursts and gas emissions have led to major advances towards the recovery and development of coalbed methane for commercial use thus coalbed methane as a mining hazard was harnessed as a conventional gas resource

numerical modelling of microseismicity associated with longwall coal mining abstract microseismicity has long been a precursor for underground mining hazards such as rockbursts and coal and gas outbursts in this research a methodology combining deterministic stress and failure analysis and stochastic fracture slip evaluation based upon the widely accepted fracture slip seismicity generation mechanism has been developed to simulate microseismic events induced by longwall mining using the built in dfn facility in flac3d discrete fractures following a power law size distribution are distributed throughout a 3d continuum model in a probabilistic way to account for the stochastic nature of microseismicity the dfn based modelling approach developed was adopted to simulate the evolution of microseismicity induced by the progressive face advance in a longwall top coal caving ltcc panel at coal mine velenje slovenia at each excavation step global stress and failure analysis with reference to the strain softening post failure behaviour characteristic of coal and fracture slip evaluation for microseismicity are conducted sequentially the model findings are compared to the microseismic event data recorded during a long term field monitoring campaign conducted at the same ltcc panel it was found that the released energy and frequency magnitude distribution of microseismicity are associated with the slipped fracture sizes and fracture size distribution these features for recorded microseismic events were fairly constant until a xylite rich heterogeneous zone ahead of the working face was approached which indicates that fractures within the extracted coal seam follow the same size distribution the features obtained from modelled microseismic events were consistent over the production period and matched well the field observations furthermore the model results indicate that the power law fracture size distribution can be used to model longwall mining induced microseismicity this model provides a unique prospective to understand longwall coal mining induced microseismicity and lays a foundation to predict microseismicity or even rockburst potential in specific geological realisations

seismic monitoring and analysis of excessive gas emissions in heterogeneous coal seams abstract uncontrolled and excessive gas emissions pose a serious threat to safety in underground coal mining in a recently completed research project a suite of monitoring techniques were employed to assess the dynamic response of the coal seam being mined to longwall face advance at coal mine velenje in slovenia together with continuous monitoring of gas emissions two seismic tomography measurement campaigns and a microseismic monitoring programme were implemented at one longwall top coal caving panel over 2000 microseismic events were recorded during a period of four months over the same period there also was a recorded episode of relatively high gas emission in the same longwall district in this paper a detailed analysis of the processed microseismic data collected during the same monitoring period is presented specifically the analysis includes the spatial distribution of the microseismic events with respect to the longwall face advance the magnitude of the energy released per week and its temporal evolution examination of the spatial distribution of the recorded microseismic events has shown that most of the microseismic activity occurred ahead of the advancing face furthermore the analysis of the gas emission and microseismic monitoring data has suggested that there is a direct correlation between microseismicity and gas emission rate and that gas emission rate tends to reach a peak when seismic energy increases dramatically it is believed that localised stress concentration over a relatively strong xylite rich zone and its eventual failure which was also identified by the seismic tomography measurements may have triggered the heightened microseismic activity and the excessive gas emission episode experienced at the longwall panel monitored

the relationship between acoustic emission and permeability of rock under stress abstract the results of research into an assessment of the applicability of high frequency acoustic emission techniques to the prediction of gas outbursts are reported simultaneous measurements of acoustic emission and permeability under triaxial compression have been conducted on outburst prone sandstone the results show that the changes in acoustic emission activity and permeability occur together at the dilatancy stage this relationship was considered theoretically the agreement between the theoretical and experimental results shows that the high frequency acoustic emission method is very promising for predicting gas outbursts the high frequency acoustic emission measurements in the field at polish collieries have been successfully interpreted in terms of permeability changes

inverse estimation of rock thermal conductivity based on numerical microscale modeling from sandstone thin sections abstract the effective thermal conductivity etc of porous rocks is primarily controlled by the matrix thermal conductivity mtc and the thermal conductivity of the pore fluid as a function of porosity rock etc has been investigated widely however information on mtc is rather sparse this study proposes a new approach using a numerical model to determine the mtc of porous rocks by parameter fitting to the measured etc the model represents realistic rock textures as detailed information on grain and pore geometries was obtained from microscopic images of thin sections mtc fitted from water saturated condition water as pore fluid showed plausible values between 4 9 and 7 6 w m k while mtc values from dry condition air as pore fluid were disproportionate except for one model with consistent mtc for both conditions this supports the idea that at constant temperature and pressure mtc is an intrinsic property independent of fluid saturation for this reason mtc from water saturated condition was used to calculate dry etc the model showed lower dry etc than the lab measurements but within a reasonable range for dry sandstones investigation of etc regarding saturation degree revealed that the samples may contain 12 45 residual moisture which explained the higher measured dry etc additionally the models allowed observation of textural influences showing that grain size distribution and connectivity affected the heat conduction of porous rocks

in situ identification of high vertical stress areas in an underground coal mine panel using seismic refraction tomography abstract because high stress anomalies can induce dynamic failures in the underground panels of coal mines the identification of high stress areas is critically important for mining safety we have identified areas of high vertical stress of an in situ longwall panel with seismic refraction tomography and interpreted our results using rock physics models constrained by core measurements since p and s velocities in rocks are stress sensitive mapping of them can provide useful information to identify areas of potential high stress we have inverted p and s velocities of main roof of an in situ panel with refraction tomography and converted them into vertical stress estimates using a calibration function from core measurements those estimates are classified into three groups high medium and low respectively identified zones of high vertical stress show qualitative agreement with monitored in panel microseismic data zones derived from p waves give a more plausible assessment than s waves we also discuss the link between high vertical stress areas and in panel faults because of the impact of the regional stress field and previously mined out voids the existing fault zone affects the redistribution of vertical stress in the underground panel

microseismic frequency spectrum evolutionary rule of rockburst triggered by roof fall abstract strong rockburst disaster in deep coal mines is easily triggered by the higher static stress of mining coal seam and the dynamic stress wave disturbance generated by hard and thick roof fall revealing the frequency spectrum evolutionary rule of microseismic ms signals before and after roof fall is a very important issue for evaluating and forecasting rockburst danger by experimental tests for combined coal and rock samples rockburst failure and in situ measurements in a strong rockburst coal mine the frequency spectrum evolutionary rule and precursory characters were analyzed in detail the following conclusions were drawn 1 precursory ms signals show the elevated energy and events lower frequency and trend of spectrum moving to low frequency band 2 mainshock signals of rockburst are characterized by maximum amplitude vibration velocity wider spectrum and higher predominant frequency and 3 aftershock signals are characterized by the sudden decreasing amplitude highest predominant frequency and trend of spectrum moving to high frequency band

earthquake induced unusual gas emission in coalmines a km scale in situ experimental investigation at laohutai mine in the present study a km scale in situ experiment was carried out at laohutai coalmine in fushun city china to investigate the possibility of earthquake induced unusual methane gas emission in coalmines the motivation of this study was attributed to the observation of a series of coalmine gas explosion accidents in china and the incidental strong earthquakes that seemed to be related to these accidents laohutai coalmine was chosen as the experiment base because of its high methane content in the coal body and its past and current active rockburst activities the mechanisms of rockbursts and earthquakes are the same i e both are violent failure of rock masses and geological structures due to stressing or straining detailed microseismic event and gas content monitoring programs were carried out at the mine site and combined with field inspection by experienced engineers a large amount of data were collected and analyzed it is revealed that there is a good correlation between rockburst and high methane gas emission events at the mine site high gas emissions have been observed before during and after rockburst events therefore an analogy can be made from the findings of this study i e unusual gas emission can happen in coalmines before during and after an earthquake when gas content is high and all boundary conditions are met both rockbursts and earthquakes can trigger unusual gas emission and sometimes the gas gushes are violent enough to fit into the category of gas outbursts on the other hand gas gushes can also trigger rockbursts in coalmines this type of rockburst which is called gas outburst rockburst is triggered by the coupling between the unloading of the porous material and the gas storage structures and the expansion due to desorption of methane gases a fractal relationship between seismic energy and influence radius is derived it is suggested that methane gas emission warnings could be provided to coalmines located within the influence radius when releasing earthquake risk warnings

numerical modelling of anomalous microseismicity influenced by lithological heterogeneity in longwall top coal caving mining abstract mining induced microseismicity has been extensively used to evaluate the potential for rock bursts and coal and gas outbursts in underground coal mines in a research project completed a few years ago it was observed that characteristics of microseismicity around a working longwall panel were fairly consistent over the monitoring period until a lithological heterogeneity zone with a relatively high coal strength was reached the current research presented in this paper aims at achieving a better understanding of the effect of lithological heterogeneity on microseismic activity in longwall coal mining the heterogeneous zone inferred from the tomography measurements was first digitalised and implemented into a 3d geomechanical model a microseismicity modelling approach which combines deterministic stress and failure analysis together with a stochastic fracture slip evaluation was used to simulate the evolution of microseismicity induced by the progressive face advance passing through the heterogeneous zone the heterogeneity was taken into account by varying the material strength and the fracture attributes of the elements within the high strength zone results have shown that both the high rock strength of coal lithotype and low power law scaling exponent of fractures within this zone contribute to the reduction in fitted b values from frequency magnitude distribution of microseismicity and the increase in fitted gaussian distribution parameters to the logarithmic event energy these deviations are believed to result from the combined effects of increased stress drops and slipped fracture sizes when the heterogeneous zone is approached

natural baseline quality of madrid tertiary detrital aquifer groundwater spain a basis for aquifer management the madrid tertiary detrital aquifer is one of the largest and most important aquifers of spain this paper assesses the most relevant controls on the natural baseline quality and the dominant chemical processes within the aquifer the hydrochemistry of the groundwater is variable despite the relative uniformity of the detrital sediments the natural baseline is expressed as a range of values that are controlled by lithological and hydrological factors spatial variations of groundwater chemistry are related to changes in rock type water rock interaction and the residence time of groundwater the fundamental chemical processes within the arkosic aquifer are hydrolysis of silicates dissolution of carbonates dissolution of evaporites only in the vicinity of the transitional facies ion exchange neoformation of clays precipitation of silica as cement and precipitation of carbonates due to increasing temperature along the downward pathways some chemical and physico chemical parameters like ph dissolved oxygen and hardness and several elements like calcium sodium magnesium silica and arsenic show an evolutionary trend according to groundwater flow path a gradual increase in arsenic concentration from recharge areas to discharge areas is observed it is the main natural water constituent that deteriorates the quality of the fresh madrid groundwater as a drinking water supply the occasionally elevated arsenic concentrations originate from natural sources the concentration and mobility of arsenic seems to be controlled by ph dependent anion exchange processes resulting from the evolution to na hco3 water

numerical simulation of progressive rock failure and associated seismicity in this paper a numerical approach to modeling progressive failure leading to collapse in rock and associated seismicity is reported in the first part a newly developed numerical code rfpaz rock failure process analysis is introduced the program allows modeling of the observed evolution of damage and associated seismic events due to progressive failure leading to collapse in brittle rock there are three features distinguishing the approach from conventional numerical methods such as fem 1 by introducing heterogeneity of rock parameters into the model rfpaz can simulate non linear behavior in rock using a linear method 2 by introducing elastic modulus reduction for failed elements rfpa2d can process discontinuum mechanics problems by a continuum mechanics method and 3 by recording the event rate of failed elements the seismicities associated with the progressive failure in rock can be simulated in the second part of the paper the applications of rfpa2d in simulating geological process and in solving mining design problems are illustrated numerical simulation of a fault initiation process indicates that some of the important phenomena such as coalescence of microfracture the nucleation and growth of crack clusters fault initiation and development elastic rebound dilatation uplift and seismic behavior etc can be simulated with this numerical code the simulation of progressive failure leading to collapse in underground openings demonstrates the capacity of this code in solving mining design problems