Mining_Methods_UnderGround_Mining - Mining and Blasting

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Boxhole boring. raiSe BOring production. Standard RBMs are capable of boring at angles between 45 degrees and 90 degrees from horizontal, and with minor adjustment can actually bore at angles between 45 degrees and horizontal. A whole host of methods of mechanical raise and shaft excavation have been developed around the use of the RBM. These include boxhole boring, blind shaft boring, rotary drilling, down reaming, pilot up/ream down, pilot down/ ream down, hole opening, and BorPak. alternative boring methods Boxhole boring is used to excavate raises where there is limited access, or no access at all, to the upper level. The machine is Clearance for derrick erection from the transporter system Typical raise boring underground site showing overhead clearance. set up at the lower level, and a full diameter raise is bored upward. Stabilizers are periodically added to the drill string to reduce oscillation and bending stresses. Cuttings gravitate down the hole and are deflected away from the RBM at the lower level. Blind shaft boring is used where access to the lower level is limited, or impossible. A down reaming system is used, in which weights are attached to the reamer mandrel. Stabilizers are located above and below the weight stack to ensure verticality of the hole. Cuttings are removed using a vacuum or reverse circulation system. Rotary drilling is used for holes up to 250 mm-diameter, and is similar in concept to pilot hole drilling in that a bit is attached to the drill string to excavate the required hole size. Down reaming involves drilling a conventional pilot hole and enlarging it to the final raise diameter by reaming from the upper level. Larger diameter raises are achieved by reaming the pilot hole conventionally, and then enlarging it by down reaming. The down reamer is fitted with a non-rotating gripper and thrust system, and a torque-multiplying gearbox driven by the drill string. Upper and lower stabilizers are installed to ensure correct kerf cutting and to reduce oscillation. Pilot up/ream down was a predecessor of modern raise boring techniques using standard drilling rigs. Pilot down/ ream down, or hole opening, employs a small diameter reamer to follow the Overhead clearance for complete derrick extension pilot hole. Stabilizers in the drill string prevent bending. The BorPak is a relatively new machine for blind hole boring which climbs up the raise as it bores. It comprises a guided boring machine, power unit, launch tube and transporter assembly, conveyor and operator console. Cuttings pass through the centre of the machine, down the raise and launch tube, and onto the conveyor. The BorPak has the potential to bore holes from 1.2 m to 2.0 mdiameter at angles as low as 30 degrees from horizontal. It eliminates the need for a drill string and provides the steering flexibility of a raise climber. raise boring machine The raise boring machine (RBM) provides the thrust and rotational forces necessary for boring, as well as the equipment and instruments needed to control and monitor the process. It is composed of five major assemblies: the derrick; the hydraulic, lubrication, and electrical systems; and the control console. The derrick assembly supplies the rotational and thrust forces necessary to turn the pilot bit and reamer, as well as to raise and lower the drill string. Base- plates, mainframe, columns and headframe provide the mounting structure for the boring assembly. Hydraulic cy- linders provide the thrust required for lowering and lifting the drillstring, and for drilling and reaming. The drive train assembly, comprising crosshead, main drive motor, and gearbox, supplies the 26 underground mining methods
Typical operating installation of the BorPak machine. rotational power to the drill string and cutting components. Four types of main drive motor systems are available: AC, DC, hydraulic and VF. The gearbox mounts directly to the main drive motors, Robbins 73RM-VF set up in a workshop. employing a planetary reduction for its compactness. The hydraulic power unit is skid-mounted, and comprises the necessary reservoir, motors, pumps, valves, filters and manifolds. The lubrication system ensures proper delivery of lubricating oil to the raiSe BOring high-speed bearings and other selected components of the drive train assembly gearbox, and comprises pump, motor, filter, heat exchanger, flow meter, and reservoir with level gauge, thermometer and breather. The electrical system assembly consists of an enclosed cabinet containing the power and control distribution hardware and circuitry for the entire raise boring operation. The control console provides for both electrical and hydraulic functions, offe- ring meter readouts for main operating parameters. Computerization of the raise boring functions is also offered, using Atlas Copco’s well-tried PC based RCS system. acknowledgements This article has been prepared using The Raise Boring Handbook, Second Edition, researched and compiled by Scott Antonich, as its main reference. underground mining methods 27
Page 1 and 2: Mining Methods in Underground Minin
Page 3 and 4: Contents Foreword 2 Foreword by Han
Page 5 and 6: Mining TrendS Trends in underground
Page 7 and 8: Rock production (2005) Ore (Mt) noi
Page 9 and 10: geOlOgy FOr Mining geology for unde
Page 11 and 12: Sandstone. Gneiss. Many salts, for
Page 13 and 14: drives within the mineral deposit,
Page 15 and 16: Mineral prospecting and exploration
Page 17 and 18: Atlas Copco underground core drilli
Page 19 and 20: Finding the right balance in explor
Page 21 and 22: % 100 80 60 40 20 0 Canada latin am
Page 23 and 24: Mine inFraSTruCTure underground min
Page 25 and 26: pumphouses and workshops. Drill/bla
Page 27: Principles of raise boring efficien
Page 31 and 32: MeCHanized BOlTing Mechanized bolti
Page 33 and 34: on the latest Boomer and Simba seri
Page 35 and 36: Mining in steep orebodies Based on
Page 37 and 38: main level, providing access and ve
Page 39 and 40: waste ratio during a typical muckin
Page 41 and 42: Mining in flat orebodies nearly hor
Page 43 and 44: crosscut drift Foot wall (The Fossu
Page 45 and 46: BaCkFilling Backfilling for safety
Page 47 and 48: Thickener Binder cement and/or slag
Page 49 and 50: History Mining has been conducted a
Page 51 and 52: 0.1% Cu, 99 g/t Ag and 0.3 g/t Au.
Page 53 and 54: This joint development process star
Page 55 and 56: zinkgruVan, Sweden Changing systems
Page 57 and 58: longhole open stoping has contribut
Page 59 and 60: flexibility during drilling and bol
Page 61 and 62: increasing outputs at lkaB iron ore
Page 63 and 64: 2 Groups of ore passes 7 Developmen
Page 65 and 66: keMi, Finland From surface to under
Page 67 and 68: The crusher station at the 560 m le
Page 69 and 70: Kemi is carrying out slot hole dril
Page 71 and 72: JelSˇ aVa, SlOVakia Mining magnesi
Page 73 and 74: Pillar between stopes 5.0 m-high, b
Page 75 and 76: kure, Turkey all change for asikoy
Page 77 and 78: m along the footwall contact, or in
Page 79 and 80:
History The El Soldado and Los Bron
Page 81 and 82:
Max 15.0 m Ventilation shaft 17 to
Page 83 and 84:
Simba M6 C drilling radial holes. a
Page 85 and 86:
Pioneering mass caving at el Tenien
Page 87 and 88:
caving in primary rock. Currently,
Page 89 and 90:
Production area 5 4 80 m 57,5 m 22,
Page 91 and 92:
used is again panel caving with pre
Page 93 and 94:
introduction Codelco, renowned for
Page 95 and 96:
During pilot hole drilling and rea-
Page 97 and 98:
40 m in length were drilled each mo
Page 99 and 100:
anTOFagaSTa, CHile Modernization at
Page 101 and 102:
MOunT iSa, auSTralia Mount isa mine
Page 103 and 104:
4500N Advance south Stoping sequenc
Page 105 and 106:
to the hanging wall. The fill used
Page 107 and 108:
MelBOurne, auSTralia High speed hau
Page 109 and 110:
The Minetruck MT5010 exits from the
Page 111 and 112:
geology The Olympic Dam mineral dep
Page 113 and 114:
Activity Overview Mucking Overview
Page 115 and 116:
on site. Later stopes, which are no
Page 117 and 118:
improved results at Meishan iron or
Page 119 and 120:
ig, six hours/shift, two shifts/day
Page 121 and 122:
Mechanized mining in low headroom a
Page 123 and 124:
large scale copper mining adapted t
Page 125 and 126:
tricky, because the pillars in the
Page 127 and 128:
gerMany/SOuTH kOrea underground min
Page 129 and 130:
which are spread over 10-130 Mpa. A
Page 131 and 132:
CaMPO FOrMOSO, Brazil Sub level cav
Page 133 and 134:
Slot drilling at Ferbasa: The Simba
Page 135 and 136:
getting the best for Peñoles Speci
Page 137 and 138:
They went from drilling 20 m downwa
Page 139 and 140:
keeping a low profile at Panasqueir
Page 141 and 142:
Boomer S1 L drill rig in operation.
Page 143 and 144:
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