Geomechanical conditions for quasi-resonances in geomaterials and block media

Conclusions  Based on voluminous information about relations between the dimensions of the central zones of crustal earthquakes and various energy classes of underground explosions, as well as mine shocks and man-induced tremors, therefore, the hypothesis that we had previously advanced relative to the quasi-resonant mechanism of their manifestation is confirmed. Here, the geomechanical conditions for the development of quasi-resonances associated with the inducement of pendulum waves are characterized by the dimensionless energy criterion k:

Specific Energy Prediction for Circular Diamond Saw in Cutting Different Types of Rocks Using Multivariable Linear Regression Analysis

Circular diamond saw performance is affected by a variety of factors. The principal factors requiring consideration when predicting cutting rates are the type and operating features of a diamond saw and the rock characteristics. The laboratory experimental tests are carried out on three groups of rocks (16 types) cut with the help of three types of diamond disk saws with different feed rates and cutting depths at constant peripheral velocity. The quantitative determinations of a wide range of textural, mechanical, and intact properties of rocks are also made. The relationship between the specific cutting energy SE _cut of the sawblade operating parameters and rock properties is established. Applying multivariable linear regression analysis, the predictive model of SE _cut is developed based on the rock property data. Models verified by statistical tests prove their practical validity. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 56–80, May–June, 2005.     

Conditions for the formation of a “particle-bubble” flotation complex

An estimate is given for the minimum distanceh _i at which a particle may approach a bubble during collision under action of forces of a hydrodynamic nature. The thicknessh _crit of the film separating the objects being acted upon is calculated when the film fails spontaneously. The collision is considered effective if the conditionh _crit≥h_i is fulfilled. Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 94–103, March–April, 2000.     

Stress-field evaluation by geostructural and geomechanical prospection: The case history of the machaerus rock-mass (Hashemite Kingdom of Jordan)

On the bases of a field geostructural and geomechanical survey, we evaluate the stress field and structural regime responsible for the deformation of the rock-mass in the Machaerus area, the Hashemite Kingdom of Jordan, on the eastern side of the Dead Sea Transform Fault. The resulted data are compared to those from deep mines and base tunnels in order to evaluate the potentiality of using geostructural data to envisage the stress-field for new geoengeneering projects. It resulted the Machareus rock mass was deformed at a depth of about 500–900 m with a deviatoric stresses of the order of σ ₁ =15 MPa, σ ₂ =10 MPa and σ ₃ =−25 MPa, being σ ₃ vertical. The stress field orientation is consistent with the left-lateral kinematics of the nearby Dead-Sea transform fault.     

Experimental investigation of divergence of confined turbulent jets

Conclusions The author gives the results of experimental investigations of confined turbulent flows between two parallel surfaces with sudden broadening of the cross section of the channel followed by narrowing. They find that the angle of divergence of the jet does not depend on the initial speed of the incoming current to the chamber, u_ic, or the length of the inlet channell _ic and is equal to about 20° as long as the formation of the main jet is not subjected to the confining effect of the side walls, i.e., up to m≤0.3. If the jet cross section is m>0.33 and the inlet and outlet channels are symmetrical relative to the width of the chamber and on the same axis, there is “adhesion” of the jet to one of the side walls on account of the pressure redistribution. The length of the circulation zone depends linearly on the jet confinement parameter B_r/2d₀, andl _R is constant for Reynolds numbers between 0.5·10⁴ and 1.6·10⁴. The results of the above investigations can be used to construct schemes of formation of currents in large-span extraction workings and analysis of their ventilation. Mining Institute, Kola Branch, Academy of Sciences of the USSR, Apatity. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 106–111, May–June, 1981.     

Reynolds number in restricted movement of mineral grains

Conclusions The authors determine the conditions of similarity for restricted motion of grains in a stream at constant velocity which are common with the conditions for free motion governed by the similarity rule of Reynolds. In the Reynolds number for restricted conditions, the characteristic parameter should be a linear quantity characterizing the thickness of the layer of liquid diverted by the body. In this case the relation between the coefficient of resistance ψ_re and the Reynolds number Re _l for restricted conditions takes the form of straight-line graphs passing through points on the Rayleigh curve corresponding to ψ₀ and Re₀ for free motion of the grains. These relations permit us to take detailed account of the variation in the degree of mutual influence between the grains in relation to their hydraulic dimensions. The expression for restricted motion of grains, based on the relation ψ_re =f(Re _l ), embraces the whole possible range of degrees of dilution of the grains and can be used in practical calculations. Mekhanobrchermet, Krivoi Rog. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 5, pp. 90–98, September–October, 1974.     

Impulsive liquid-gas fracture of brittle and ductile rocks and ways of improving the process

Conclusions 1. Other conditions being equal, an increase in the strength and fracture toughness of rock reduces mean crack velocity in impulsive hydraulic fracture and the final dimensions of the cracks within the loading-rate range 0.5·10⁹≤ ≤5·10⁹ Pa/sec. 2. Since the drag coefficient of fluid in a crack is determined by the roughness of the crack’s walls, other conditions being equal, the greatest effect from impulsive fracture should be seen in rocks with fine and cryptocrystalline structures. 3. If the coefficient that characterizes the degree to which a well is filled by combustible material is increased in value from 0.62 to 0.75, the dize of the disk-shaped tensile ruptures formed in ductile rocks increases 60–70%. 4. The main parameters characterizing the impulsive fracture of a productive bed (crack depth and width) depend more on the thermodynamic characteristics of the pressure generator in the well (injection time and pressure) than on the viscosity of the injected fluid. 5. A technology involving interval-by-interval impulsive fracture by sectional shaped charges of high explosives is recommended for strong brittle rocks of moderate and high density. Institute of Geophysics, National Academy of Sciences of the Ukraine (Kiev). Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 50–58, July–August, 1997.     

Development and Validation of a Spectrophotometric Method to Measure Sulfate Concentrations in Mine Water without Interference

Sulfate concentrations are determined in mine water by gravimetric, titrimetric, colorimetric, turbidometric, ion chromatographic, inductively coupled plasma absorption spectrophotometric, and other methods. Accurate sulfate measurement of mine water can be difficult due to interfering groups, cations, and anions, mainly arsenate (AsO₄ ³⁻) and phosphate (PO₄ ³⁻). In this paper, a simple and effective spectrophotometric method is described for the determination of sulfate in mine water. When the SO₄ ²⁻ reacts with barium chloranilate at pH 4.5 in aqueous ethyl alcohol solution, it releases acid-chloranilate, which shows maximum absorption at 350 nm and obeys Beer’s law over the concentration range of 10–1,000 mg/L. Results show that the proposed method was significantly more accurate than a conventional method. Absorbance was found to increase linearly with increasing concentration of sulfate, which is corroborated by the calculated correlation coefficient value of 0.999 (n = 7). The slope and intercept of the equation of the regression line were 0.00091 and 0.00778, respectively. The limit of detection and limit of quantification were found to be 0.03861 and 0.06774 mg/L, respectively. The validity of the described procedure was assessed. Statistical analysis of the result indicated high accuracy and good precision. The proposed method was successfully applied in mine water without interference from common groups like AsO₄ ³⁻ and PO₄ ³⁻. The relative standard deviations of the proposed method ranged from 0.03 to 0.26%, with recoveries of 99.79–101.57%.     

Energy content of the nonexplosive excavation of rock by excavators with a dynamic scoop

Conclusions  

Extraction of hydrogen cyanide from waste solutions of cyaniding circuit for sulfide flotation concentrates

The process for extraction of hydrogen cyanide to decontaminate solutions produced at cyaniding of sulfide flotation concentrates is developed. The centrifugal-bubbling apparatus is employed as a reactor. The regularities of HCN formation in an acid medium are established in investigation into kinetics of SCN⁻ thiocyanate oxidation by hydrogen peroxide H₂O₂ in presence of Fe²⁺, Fe³⁺ and pH ≤ 3.5. In the process proposed the evolved HCN is adsorbed by NaOH solution and returned to the circuit of leaching of gold and silver as NaCN, and the waste cyaniding solution is discharged into a waste dump, where it is mixed with industrial water to be utilized to transport flotation tailings. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 98–105, January–February, 2009.     

Use of fluorinated alcohols to intensify copper-nickel ore grinding

The experimental data are reported on intensification of the copper-nickel grinding by feeding fluorinated saturated mono-atomic alcohols of a general formula H - (CF₂CF₂) _n - CH₂ - OH into a mill. The feeding of this reagent into a mill at the rate of 25–100 g/t of feed provides better exposure of aggregates in the ore preparation circuit thus intensifying the subsequent ore flotation. The increment of copper and nickel recovery into a concentrate amounts to more than 4%. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 95–100, July–August, 2008.     

Tracer Test in a Settling Pond: The Passive Mine Water Treatment Plant of the 1 B Mine Pool,Nova Scotia,Canada

In order to verify why the design criteria of the Neville Street well field of the 1 B mine pool passive treatment plant were not being met, four mine water tracer tests with uranine (Na-fluorescein) and rhodamine B were conducted in the system’s settling pond. Both tracers were injected at the pond’s aeration cascade during three separate tracer tests with varying flow conditions (54–158 L s⁻¹). In addition, oxygen saturation and iron concentrations were measured during the first two tests. The aeration cascade works properly; O₂ saturation reaches 81% after less than a second. However, the mean residence time in the settling pond was determined to be only 10–18 h. The plant operator installed five baffle sheets to increase the mean residence time in the settling pond. Tracer tests with uranine after the baffle sheets were installed revealed a new mean residence time of 35 h.     

On determining the parameters of the kinetic equation of rock durability using the measurement data on tensile strength at different loading rates

The experimental tensile strength data are presented for some hard materials, that are obtained by the three-point bending at different loading rates. Owing to a wide range of change in the loading rates from 10⁻² to 10² MPa/s, constants of Zhurkov’s kinetic equation have been determined. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 3, pp. 11–17, May–June, 2006.     

Passive aerobic treatment of net-alkaline,iron-laden drainage from a flooded underground anthracite mine,Pennsylvania, USA

This report evaluates the results of a continuous 4.5-day laboratory aeration experiment and the first year of passive, aerobic treatment of abandoned mine drainage (AMD) from a typical flooded underground anthracite mine in eastern Pennsylvania, USA. During 1991–2006, the AMD source, locally known as the Otto Discharge, had flows from 20 to 270 L/s (median 92 L/s) and water quality that was consistently suboxic (median 0.9 mg/L O₂) and circumneutral (pH ≈ 6.0; net alkalinity >10) with moderate concentrations of dissolved iron and manganese and low concentrations of dissolved aluminum (medians of 11, 2.2, and <0.2 mg/L, respectively). In 2001, the laboratory aeration experiment demonstrated rapid oxidation of ferrous iron (Fe²⁺) without supplemental alkalinity; the initial Fe²⁺ concentration of 16.4 mg/L decreased to less than 0.5 mg/L within 24 h; pH values increased rapidly from 5.8 to 7.2, ultimately attaining a steady-state value of 7.5. The increased pH coincided with a rapid decrease in the partial pressure of carbon dioxide (PCO₂) from an initial value of 10^−1.1 atm to a steady-state value of 10^−3.1 atm. From these results, a staged aerobic treatment system was conceptualized consisting of a 2 m deep pond with innovative aeration and recirculation to promote rapid oxidation of Fe²⁺, two 0.3 m deep wetlands to facilitate iron solids removal, and a supplemental oxic limestone drain for dissolved manganese and trace-metal removal. The system was constructed, but without the aeration mechanism, and began operation in June 2005. During the first 12 months of operation, estimated detention times in the treatment system ranged from 9 to 38 h. However, in contrast with 80–100% removal of Fe²⁺ over similar elapsed times during the laboratory aeration experiment, the treatment system typically removed less than 35% of the influent Fe²⁺. Although concentrations of dissolved CO₂ decreased progressively within the treatment system, the PCO₂ values for treated effluent remained elevated (10^−2.4 to 10^−1.7 atm). The elevated PCO₂ maintained the pH within the system at values less than 7 and hence slowed the rate of Fe²⁺ oxidation compared to the aeration experiment. Kinetic models of Fe²⁺ oxidation that consider effects of pH and dissolved O₂ were incorporated in the geochemical computer program PHREEQC to evaluate the effects of detention time, pH, and other variables on Fe²⁺ oxidation and removal rates. These models and the laboratory aeration experiment indicate that performance of this and other aerobic wetlands for treatment of net-alkaline AMD could be improved by aggressive, continuous aeration in the initial stage to decrease PCO₂, increase pH, and accelerate Fe²⁺ oxidation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Passive Treatment of Acidic Coal Mine Drainage: The Anna S Mine Passive Treatment Complex

The Anna S coal mine complex in Tioga County, PA, produces drainage with a pH of 2.8–3.6 containing 3–36 mg/L Al, 1–36 mg/L Fe, and 6–9 mg/L Mn. In 2003, the Babb Creek Watershed Association installed two systems that passively treat three discharges from the mine complex. Both systems contain four parallel vertical flow ponds followed by aerobic wetlands. The vertical flow ponds contain a total of 35,483 t of limestone and 4,913 m³ of organic substrate. During the last 6 years, the systems have treated an average of 1,971 L/min of flow to neutral pH with 135–146 mg/L of alkalinity (as CaCO₃), with less than 1 mg/L of Al and Fe, and 2–4 mg/L of Mn. The vertical flow ponds have generated alkalinity at rates of 32–53 g/m²/day as CaCO₃. No seasonal variation in treatment effectiveness has been observed, despite relatively harsh winter seasons. The total cost of the passive systems was $2.5 million (US). The 20 year projected unit treatment cost, including periodic replacement of the organic substrate, is $2.5 million (US). The 20 year projected unit treatment cost, including periodic replacement of the organic substrate, is 403–618 per t (as CaCO₃) of net alkalinity generated.     

Experimental investigation of plastic pure-shear deformation under simple and complex loadings

Conclusions The inelastic properties of solid bodies under simple and complex loadings that result in pure-shear strain and successive superposition of deformed states of pure shear are investigated experimentally. The strain anisotropy that develops in this case is satisfactorily described by the hypothesis of anisotropic hardening, which must be considered in constructing constitutive relationships of the theory of plasticity of rocks. For these types of loads, there are uniqueσ _i(ɛ _i) andσ ₁(ɛ ₁) cuves that can be used as rating curves for the material in calculations. These effects may be used as a production procedure for controlling the anisotropy of the metal in tubular structural components in mining-machine building and the creation of prescribed (improved) strength properties in these components. Mining Institute, Siberian Division of the Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 33–46, January–February, 1998.     

One approach to the prediction of rock bursts

Conclusions Thus, as a result of the experimental discovery of previously unknown pendulum waves, the elementary carriers of which are geoblocks differing in hierarchic level, with dynamic-kinematic characteristics that depend on the stress-strain state of the rock masses and the dimensions of the focal zones of rock bursts and explosions, we are able to propose a new approach to the prediction of catastrophic events. Here, as diagnostic indexes with respect to the critical stages of stress concentration for focal zones of rock bursts that are being formed, we can use the angular characteristic θ of the conical envelope of the μ-wave packets and their energy characteristics Ψ₁ and Ψ₂. With such an approach, seismograms from technological explosions can be used as integral information in a new system of geomechanical monitoring. Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 6, pp. 3–15, November–December, 1998.     

Estimating the stress and strain fields of the Earth's crust on the basis of seismotectonic data

A method is proposed for estimating the lateral pressure coefficientsq _x ,q _y on the basis of seismological data (the principal stress or principal strain trajectories). Results obtained by this method for the iron-ore deposits of Gornaya Shoriya are in good correlation with in-situ data. For the main tectonic regimes (normal faults, strikeslip faults, thrust faults), the range ofq _x ,q _y variation is established, and the conditions for the application of two-dimensional models and relation for which motion along fracture disturbances is possible are determined. Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 28–36, January–February, 1999.     

Reaction of fluids of an oil-producing stratum to low-intensity vibro-seismic action

A full-scale study is made of the effect of a vibro-seismic field of the intensity 10⁻⁷-10⁻⁶ W/m² on the properties and composition of oil and associated gas. The long-term character of this effect is demonstrated. An examination is made of the main processes responsible for important changes in the stratum fluids when an oil pool is subjected to vibro-seismic action from the surface. Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 11–17, March–April, 1999.