WATER JET CONFERENCE - Waterjet Technology Association

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Figure 10. Bentonite drilled clay samples Figure 11. System hourly operating cost as a function Figure12. System operating of usage. cost on a per foot basis. 337
<strong>WATER</strong> <strong>JET</strong> ASSISTED MINING TOOLS: WHAT TYPE ASSISTANCE AND WHAT TYPE MINING MACHINE? L. M. Ford Geotechnical Engineering Division Sandia National Laboratories Albuquerque, NM 87185 ABSTRACT Water jet assisted mining tools have been discussed in the literature for many years, but virtually no discussion exists of the specific modes of assistance and the benefits to be derived from each. This paper will identify two modes of assistance and show the effects that each has on the specific energy related to rock cutting. The cutting mechanism of a mining tool without water jet assistance will be examined briefly and its effect on tool spacing on a mining machine developed. Next the effects of kerfing (cutting thin slots) on specific energy will be examined and a technique for the optimization of kerf spacing and kerf depth as a function of depth-of-tool-cut will be presented. A discussion of the stable crack extension mode will be presented and its effectiveness shown. Finally the requirements for a mining machine which could take maximum advantage of these assistance modes will be presented. INTRODUCTION Water jets, because of the great range of operational parameters, are used for many tasks. One use of water jets is to cut rock or to assist mechanical tools used for cutting rock. Two mechanisms by which water jets create a failure in the rock are: (I) erosion of the rock by removing or weakening the material cementing the grains together and removing the grains with hydrodynamic drag forces (Rehbinder, 1980; Crow, 1973) and (2) hydraulic crack extension (Hood, 1977). The efficiency of these water jet mechanisms depends on several factors: (I) water pressure at the nozzle, (II) nozzle diameter, (III) traverse rate, and (IV) rock properties. When used in conjunction with mechanical cutting tools, water jets also improve the cutting efficiency by lubricating the cutting surface and by removing rock chips. This paper is concerned with the overall efficiency of the mining process. The overall efficiency is affected by the individual efficiencies of the cutting devices. Therefore, the individual processes and their efficiencies will be examined. The results will then be applied to describe the characteristics of a mining machine which can best utilize the most efficient mechanisms and characteristics. This work is supported by the U. S. Bureau of Mines, Pittsburgh Research Center. 338
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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
Page 294 and 295: The coefficients "b " in Eq. (1) ca
Page 296 and 297: By the end of 1982, a total of more
Page 298 and 299: Figure 4. Cutting ability of swing-
Page 300 and 301: Figure 10. An operating performance
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Page 308 and 309: Table 1. Concrete saw technology. T
Page 310 and 311: NAME: Tom Brunsing COMPANY: Foster-
Page 312 and 313: FEASIBILITY STUDY OF CUTTING SOME M
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Page 316 and 317: pressure was varied from 103 to 310
Page 318 and 319: 2.1 Heading and gutting fresh cod f
Page 320 and 321: Figure 5. The cuts surface of a blo
Page 322 and 323: Figure 17. Cuts made across the cla
Page 324 and 325: JET NOTCHING USED IN THE CONSTRUCTI
Page 326 and 327: Bottom notch diameter was determine
Page 328 and 329: σ H = in-situ stress in the horizo
Page 330 and 331: Figure 3. Final block displacement.
Page 332 and 333: Figure 8. Comparison of Slurry Pump
Page 334 and 335: THE FURTHER DEVELOPMENT OF AN UNDER
Page 336 and 337: use taps or hydrants. To achieve th
Page 338 and 339: 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 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 390 and 391: out thoroughly an efficient scheme
Page 392 and 393: Research analysis has proved that t
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DEPENDENCE OF POWER INDICES OF COMB
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The experiments have shown how the
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K Ay = coefficient correcting for f
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Figure 1. Schemes of combined break
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Figure 5. Dependence of specific en
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Figure 12. Percentage of grade R -6
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Figure 1. Particle size analysis. T
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NAME: Dr. Henkel COMPANY: Bergbau-F
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presented. This study, of course, i
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identifying a general trend for the
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Effect of Abrasive Hardness, Shape
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In some situations, especially in c
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Figure 1. Abrasive waterjet nozzles
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Figure 8. Effect of standoff distan
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Figure 13. Abrasive waterjet cuts i
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CUTTING WITH ABRASIVE WATERJETS M.
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3.3 Abrasive Feed Systems For abras
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Because of the large number of infl
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due to wear. Although actual operat
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from this new technology. Table 2 l
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Table 1. materials cut by abrasive
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Figure 1. Abrasive waterjet nozzles
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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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