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out thoroughly an efficient scheme for the combined breakage and to establish its rational parameters and dependences: P z,P y,P x,H w,R -6,R +25,= (h,t,h s,a,d, δ,k) (1) Advantages of the hydromechanical method for coal breakage were defined by a comparative research of the mechanical and hydromechanical methods. The research was carried out by breaking a coal-cement block on a planer. A tensodynamometer (with an amplifier 8ANCh-7M and an oscillograph H-115) was fixed on the support of the planer to register the force parameters of the process. A special hydromechanical device was attached to the dynamometer Water was supplied to the device by two pumps (water pressure up to 55 MPa, water discharge 200 l/min.). The stand was provided with a special device to collect the dust formed by breaking the coal block. CHARACTERISTICS OF COAL MASSIF COMBINED BREAKAGE AND DETERMINATION OF ITS RATIONAL SCHEME The research has proved that for the breakage while h s> h the depth of slot cut by a water jet does not tell upon P z, P y and P x and upon the energy consumption H w because the pillars (being heterogenious) are broken at a smaller height than the depth of slot. When h s > h, the deeper the slot, the more reduced the force parameters of the process and the specific energy consumption for mechanical breakage, because a bigger h s provides for a smaller area of contact of the cutter with the coal massif and a lower pillar resistance to breakage. For all the breakage schemes any increase of the parameters h and t leads to a reduction of the energy consumption H w according to the curve dependences, and it reaches the minimum at its certain rational values which correspond to the maximum volume of breakage. Any further increase of the mentioned parameters leads to a higher specific energy consumption because the volume of breakage remains practically constant, while the rolling force of the disc cutter increases. It is determined that when the disc cutter is introduced directly in the inter-slot pillar (Fig. l,a), its breakage happens along the direction perpendicular to the plane of rolling of the disc cutter and provides for a considerable output of coal fines. Whereas the disc cutter introduced in the slot formed by the water jet provides for breaking the coal massif due to the tension and bending moment both perpendicular to the plane of rolling of the disc cutter and along its movement in the slot. That is why the cutting force P z is by 1.3-1.5 times and the energy consumption H w is by 3.0-3.5 times greater for the front scheme than for the one-sided and two-sided schemes of breakage. So the front scheme is responsible for output of about 30 per cent of coal grade 0-6 mm (which is by 4-5 times more than that of the one- and two-sided schemes) while its output of coal grade +25 mm is but almost 2 times less. 383
After this research of the schemes of breakage by a water jet together with a disc cutter with double-sided wedge rim it is established that the best results are obtained by the one-sided scheme of breakage with a floating disc cutter (Fig. l,d). The floating attachment has made it possible to completely exclude the side thrust P x, to reduce P z by 1,3-1,8 times and P y by 2.4-4.8 times (Fig. 2), to cut the energy consumption H w by 20-60 per cent (Fig. 3) and to improve the coal grade Ref. 6) what cannot be provided for by the rigid attachment of the disc cutter. For rigid attachment the inter-slot pillar breakage is accompanied by a considerable pressure exercised over the side surface of the coal massif part left, because all the time the disc cutter affects not only the side surface of the pillar which it breaks, but also the side surface of the pillar which it leaves unbroken. As the one-sided scheme allows to shear the pillar by parts both perpendicular to the plane of the disc cutter rolling and ahead of it along the slot, then, in case of the rigid attachment the sides of the disc cutter wedge rim affects the side surfaces of the pillar as well as the part of the massif left. This takes place only during wedging out the pillar by the disc cutter. It lasts till the tensile stress and tension grew sufficient enough to break this part of the pillar. After this moment the disc cutter moves along its axis and away from the side surface of the pillar left until it comes across the next virgin part of the pillar. Due to a wedge-like shape of its rim, the disc cutter enters the slot by moving along its axis towards the side surface of the massif which is left, in order to get wedged out between it and the pillar to shear the pillar. So, the floating attachment of the disc cutter helps to considerably reduce the area of its contact with the side surface of the part of the massif left unbroken, thus practically completely eliminating the side thrust effect on its axis. However, the one-sided scheme of breakage by a double-side wedge rim disc cutter has but a certain demerit. While rolling the disc cutter touches not only the side surface of the pillar to be broken but also the side surface of the coal massif left unbroken. It tells negatively upon the process parameters. The research results of the breakage schemes (Fig l,e,f) have demonstrated that when the disc cutter enters the slot at a depth h> h s, the inter-slot pillar is sheared by large lumps practically along its base which is subjected to the maximum tensile stress. When rolling along the slot the disc cutter affects not only the side surface of the pillar by its side rim, but also shears the base of the pillar by pressing its top in the massif. This results in reducing the energy consumption for hydraulic breakage considerably because the depth of slots required is smaller. So,the energy consumption H w was reduced by 25-40 per cent while the energy consumption E o was cut by 3-4 times by application of the breakage scheme with a depth h > h s, as compared with the thrust depth h < h s (Fig. 4). By introducing the disc cutter in the base of the pillar it has become possible to cut the output of 0-6 mm coal grade almost by 3 times and to increase the output of +25mm coal grade by 35-45 per cent. The scheme of breakage by a water jet and a single-sided wedge rim disc cutter with h > h s (Fig l,f) is found out to be most efficient and to provide for the minimum specific energy consumption for the mechanical and hydromechanical breakage. 384
Page 1 and 2:
Proceedings of the Second U.S. WATE
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Visualization of the Central Core o
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A Status Report on the Conceptual D
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SESSION 7 - CIVIL & INDUSTRIAL Chai
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Cutting Hard Rock With Abrasive-Ent
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frictional and piping component rel
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R = a1 ⋅ A1 A2 a2 I = 2H o Q o
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attenuation of the output. The tran
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Figure 1. Branch System Modulator F
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Figure 5. Modulation Response for B
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Figure 9. Modulation response for s
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can be used for any form of input.
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with a cylindrical shape to the jet
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m/s. The range of power found from
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Figure 3. Power vs nozzle diameter
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Figure 5. Frequency vs length of th
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NAME: Gerald Zink COMPANY: StoneAge
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modulatornozzle assembly. The ordin
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DISCUSSION OF FLUID MECHANICS The i
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This process serves to protect the
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For test purposes, these concrete b
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REFERENCES CITED 1. Barker, C. R.,
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FIGURE 4. INNER CORE OF PERCUSSIVE
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FIGURE 9. EXAMPLE OF HIGH-PRESSURE
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NAME: John E. Wolgamott COMPANY: St
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THE FOCUSED SHOCK TECHNlQUE FORPROD
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The reflected wave is thus also cyl
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neglected. The introduction of a co
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DISCUSSION NAME: George Savanick CO
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H’ mean shape factor Hj theoretic
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Required streamline curvature at th
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2 x 2 ≅ ( e − 2 p + w)/k2 (2-8)
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eliminating 2 n r 2 from equations
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approximation to the actual flow si
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skin friction coefficient but are c
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where: (H) = A1H 3 + A2H 2 + A3H +
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effect (< 0.5%) on coefficients of
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TABLE 5 Rei x 10 5 β 3 4 5 6 Po Po
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TABLE 6 D(mm) d o(mm) L t(mm) L f(m
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expanding rather than contracting a
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25. Weber, H.E., 1978, Boundary lay
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Figure 5. Wall velocity distributio
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Figure 9. Effect of nozzle design o
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Figure 12. CA+T Design Philosophy.
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Figure 16. Effect of inlet b 1 cond
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Figure 20. Relaminarization at nozz
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Figure 24. Pressure decay data. 88
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VISUALIZATION OF THE CENTRAL CORE O
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DISCUSSION Although employing the i
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5. Lambert, J. H., 1760, Photometri
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Figure 6. Spectral sensitivity curv
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NAME: W.C. Cooley COMPANY: Terraspa
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INTRODUCTION Pulsed liquid jets sho
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y=X ∨ P A dy = p p A p 2 (L c y=0
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Using equation (15), the value of X
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Thus about the first 10% of the dri
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Many design cases, including those
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surface spall occurred, resulting i
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Figure 3. Chamber pressure at pisto
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Figure 7. Effect of nozzle area rat
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Figure 11. Extrusion device schemat
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Figure 15. Typical chamber pressure
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DISCUSSION NAME: W. C. Cooley COMPA
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material which are, in turn, affect
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the water jet. This method was not
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where h is the depth of penetration
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obtained during this phase of the i
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observed that the smallest depth of
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Figure 2. Idealized Relationships b
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Figure 6. Penetration as a Function
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DEVELOPMENT OF VARIABLE DELIVERY TR
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THE STRUCTURE AND FUNCTION OF THE P
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The injection pressure can be contr
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ACKNOWLEDGEMENTS The authors gratef
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Figure 4. Theoretical required powe
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Figure 9. Variation of efficiency w
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THE "SKIPJACK" SEWER CLEANING NOZZL
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HYDRO-BLASTING SAFETY C.W. Adaway,
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Remember, your Hydro-Blasting work
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horizontal, sometimes vertical, and
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Figure 2. Safety Gear Figure 3. Tub
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DEVELOPMENTS IN CLEANING COKE OVEN
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causing chain breakages and the scr
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was encountered, then the rotation
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(C) Capital Expenditure: Material i
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Figure 9. Swivel coupling Figure 10
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OPTIMIZING JET CUTTING POWER FOR TU
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PRESSURE DROP (psi) ELEMENT Cv @10
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power output. Undersized nozzles re
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Subscripts n - Nozzle p - Pump t -
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Figure 1. Cutting effect as a funct
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CONSIDERATIONS IN THE COMPARISON OF
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pressure can be lowered to perhaps
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Figure 2: Fan jet issuing from a no
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DISCUSSION NAME: John Griffiths COM
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where Q = Flow rate - gpm D = Jet O
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Again, not limited to Newtonian flu
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REFERENCES 1. Brown, R.W. and Loper
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Table 2. Jet Cleaning Speeds and ot
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ANSWER: The utilization of the stat
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complexity and short component life
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Figure 4, for ap values ranging fro
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Decontamination Methods for rapidly
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a. “PULSER” b.”ORGAN-PIPE”
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Figure 5 - Removal rate for various
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DISCUSSION NAME: David A. Summers C
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DRILLING BORE HOLES IN COAL MINES U
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pile could not be judged as represe
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DISCUSSION NAME: David Summers COMP
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HYDRAULIC MINING EXPERIMENTS IN AN
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The monitor was fed pressurized wat
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The IH rig was considered to be sup
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REFERENCES 1. Okhrimenki, V. A., A.
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Figure 2. Jet cutting sandstone at
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Figure 5. Schematic plan view of In
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Figure 7. Suction Box. 226
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USE OF HIGH PRESSURE WATER JETS FOR
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flame torch to cut this block, redu
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the order of 360 rpm. Under these c
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Figure 3. Slot cut by jet at 11 o s
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JET-MINER SURFACE AND IN-SEAM TRIAL
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The hydraulic drive of the haulage
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The surface trials had have the obj
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Figure 2. Experimental version. Fig
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Figure. 7 Jet-Miner prototype Figur
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SOME PATTERNS OF TECHNOLOGY TRANSFE
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Development of High Pressure_Techno
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configurations, the design of an op
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and public sectors. After a haitus
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Souder, W.E. and Evans, R.J., "The
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Figure 5. Technological achievement
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Table 3. Perceived disadvantages of
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already been, or is being applied w
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Using the requirements profile and
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ant hose combination, a guiding sys
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HYDRAULIC MINING TESTS Site selecti
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SAFETY All operations were carried
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TABLE V. Categories of Jet Mining D
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Figure 2. Generalized geologic prof
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SECONDARY FRAGMENTATION WITH WATER
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do possess a maximum point (Fig. 8)
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Figure 4. Rossin-Rammler plot. Figu
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Figure 8. Non-dimensional plot for
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HYDRAULIC COAL MINING SYSTEM Typica
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Figure 4. (From ref. 1) DISCUSSION
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INTRODUCTION Developing an unique t
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The coefficients "b " in Eq. (1) ca
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By the end of 1982, a total of more
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Figure 4. Cutting ability of swing-
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Figure 10. An operating performance
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for an abrasive, the abrasive parti
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the particles, while at slower spee
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to break away the remaining segment
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Table 1. Concrete saw technology. T
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NAME: Tom Brunsing COMPANY: Foster-
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FEASIBILITY STUDY OF CUTTING SOME M
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hydraulic power required to cut thr
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pressure was varied from 103 to 310
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2.1 Heading and gutting fresh cod f
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Figure 5. The cuts surface of a blo
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Figure 17. Cuts made across the cla
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JET NOTCHING USED IN THE CONSTRUCTI
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Bottom notch diameter was determine
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σ H = in-situ stress in the horizo
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Figure 3. Final block displacement.
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Figure 8. Comparison of Slurry Pump
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THE FURTHER DEVELOPMENT OF AN UNDER
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use taps or hydrants. To achieve th
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supply line. It was determined that
Page 340 and 341: The rotating head requires major mo
Page 342 and 343: Figure 4. System field test set-up
Page 344 and 345: Figure 10. Bentonite drilled clay s
Page 346 and 347: MECHANICAL TOOLS Cutting Tool Energ
Page 348 and 349: Ψ = cos −1 ⎧ ⎪ ⎪ ⎨ ⎪
Page 350 and 351: mode also contributes to chip flush
Page 352 and 353: NAME: Simon Johnson COMPANY: Newcas
Page 354 and 355: ROLLER TOOLS COMBINED WITH HIGH-PRE
Page 356 and 357: Various designs and applications ar
Page 358 and 359: Figure 1. Full-face tunneling machi
Page 360 and 361: Figure 11. roadway profile cutting
Page 362 and 363: Figure 19. High-pressure water jet
Page 364 and 365: DESIGN AND OPERATION OF TWO LARGE-S
Page 366 and 367: The hydraulic system for the thrust
Page 368 and 369: Results of Trial Tests As part of m
Page 370 and 371: cutting rates, degree of bit wear,
Page 372 and 373: Overall approximate Weight: Basic M
Page 374 and 375: Figure 5. 3 ft. diameter laboratory
Page 376 and 377: nozzle diameter and cutting speed w
Page 378 and 379: 2. Cutting Speed The influence of c
Page 380 and 381: energy it effects an increase in me
Page 382 and 383: Tip angle (degrees) 87 Off-set angl
Page 384 and 385: Figure 5. Figure 6. Figure 7 Figure
Page 386 and 387: Figure 17. Figure 18. Figure 19. Fi
Page 388 and 389: SCHEMES OF COAL MASSIF BREAKAGE BY
Page 392 and 393: Research analysis has proved that t
Page 394 and 395: DEPENDENCE OF POWER INDICES OF COMB
Page 396 and 397: The experiments have shown how the
Page 398 and 399: K Ay = coefficient correcting for f
Page 400 and 401: Figure 1. Schemes of combined break
Page 402 and 403: Figure 5. Dependence of specific en
Page 404 and 405: Figure 12. Percentage of grade R -6
Page 406 and 407: Figure 1. Particle size analysis. T
Page 408 and 409: NAME: Dr. Henkel COMPANY: Bergbau-F
Page 410 and 411: presented. This study, of course, i
Page 412 and 413: identifying a general trend for the
Page 414 and 415: Effect of Abrasive Hardness, Shape
Page 416 and 417: In some situations, especially in c
Page 418 and 419: Figure 1. Abrasive waterjet nozzles
Page 420 and 421: Figure 8. Effect of standoff distan
Page 422 and 423: Figure 13. Abrasive waterjet cuts i
Page 424 and 425: CUTTING WITH ABRASIVE WATERJETS M.
Page 426 and 427: 3.3 Abrasive Feed Systems For abras
Page 428 and 429: Because of the large number of infl
Page 430 and 431: due to wear. Although actual operat
Page 432 and 433: from this new technology. Table 2 l
Page 434 and 435: Table 1. materials cut by abrasive
Page 436 and 437: Figure 1. Abrasive waterjet nozzles
Page 438 and 439: a) kerfs in mild steel b) S.S. 15.5
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a) circle cutting in glass b) lamin
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DISCUSSION NAME: Andrew F. Conn COM
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CUTTING HARD ROCK WITH ABRASIVE-ENT
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slurry nozzle. Testing at water pre
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DISCUSSION OF TEST RESULTS Jet Conf
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materials. The flexibility in nozzl
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pressure can be wiped out if diffic
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9. Maurer, W.C., and Heilheckler, J
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Figure 5. Effect of abrasive feed r
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Figure 9. Accumulated depth of mult
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Figure 13. Close-up view of quartzi
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ABRASIVE INJECTION USAGE IN THE UNI
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sudden changes in the feed rate eff
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or the abrasive must be manually to
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clog; there not being sufficient ar
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CODE OF PRACTICE FOR THE USE OF ABR
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Figure 5. Water abrasive cleaning h
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Figure 15. 360 0 abrasive pipe clea
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ECONOMIC CONSIDERATIONS IN WATER JE
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Other criteria to be considered in
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3 MANUAL METHODS OF JET CLEANING &
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contractor with old, unsafe, equipm
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Figure 1. Showing the increased cos
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Figure 8. Automatic tube bundle cle
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ackground to the subsequent coopera
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The molecules of SUPER-WATER posses
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shaken just before use. SUPERWATER
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26. Bednarz, L.P., "Effects of Poly
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