Headframe at Garpenberg. garPenBerg, Sweden 52 underground mining methods
zinkgruVan, Sweden Changing systems at zinkgruvan Partners in production Zinkgruvan <strong>Mining</strong>, Sweden’s third largest mining company, is owned <strong>and</strong> operated by Lundin <strong>Mining</strong> Group. Zinkgruvan <strong>Mining</strong> produces zinc concentrate (55% Zn) <strong>and</strong> lead concentrate (73% Pb <strong>and</strong> l,400 g/t Ag) <strong>and</strong> ships to smelters in northern Europe. The mine has been continuously in produc- tion since 1857, <strong>and</strong> ore output in 2006 was 787,000 t, together with around 250,000 t from waste development. Average zinc grades were high at 10.3%, whereas lead grades fell to 4.6%, <strong>and</strong> silver to 93 g/t. For 2007, ore production is planned at 850,000 t, <strong>and</strong> a pro- ject to increase reserves is underway. Zinkgruvan ore reserves total 11.2 million t, containing 9.3% zinc, 4.3% lead <strong>and</strong> 107 g/t silver, equivalent to approximately 15 years of production. Added to this, discovered in the 1990s, is a copper mineralization of 3.5 million t containing 3.1% copper <strong>and</strong> 49 g/t silver. Production is obtained from open stopes where, following difficulties with seepage from hydraulic fill when rock quality diminished, the mine now uses paste fill. Rather than deepen the main hoisting shaft, the main ramp access was developed be- low the 800 m level <strong>and</strong> will bot- tom out at 1,100 m under present plans. Key to Zinkgruvan production efforts is equipment sup- plied by Atlas Copco, which includes four Simba production drill rigs, three Rocket Boomers <strong>and</strong> two Boltec rigs, together with long-term maintenance <strong>and</strong> consumable supply contracts. Methodology Until the mid-1980s, upwards cut <strong>and</strong> fill was the dominant mining method. However, when mining began at the 650 m-level in Nygruvan, the first problems with rock stress occurred, resulting in the need for increased rock reinforcement. Longhole drilling with Simba M4 C in the Burkl<strong>and</strong> stopes. When mining reached the 566 mlevel, a borehole camera survey revealed a roof split 6 m above the stopes, causing ab<strong>and</strong>onment of cut <strong>and</strong> fill methods on safety grounds. Benching methods were introduced, <strong>and</strong> have been under constant development since, primarily because of high rock stress. Using benching, no working place need be developed wider than 7 m. Over the years, benching has developed from longitudinal bench <strong>and</strong> fill. The mined out bench is backfilled with hydraulic fill before mining the next bench above. Vertical pillars in the ore are left to stabilize the surrounding rock. Open stoping Development continued towards sublevel open stoping, which is a larger scale stoping method than longitudinal bench <strong>and</strong> fill, with improved rock stress. Sub-level open stoping as a production method worked excellently in Nygruvan, where the country rock is of extremely good quality. The ore is homogeneous, with distinct ore boundaries where dip in the ore is greater than 75 degrees. The open room that is formed after the stope is mucked has height measurements of up to 70 m, width of 15 m, <strong>and</strong> a length of 50 m. After mucking is completed, the drawpoints are sealed with bulkheads, <strong>and</strong> filled with hydraulic fill. In the mid-1990s, the Burkl<strong>and</strong> orebody was developed. Rock quality <strong>and</strong> ore geometry were different compared to earlier orebodies, <strong>and</strong> a project was initiated to utilize a modified sub-level open stoping method for orebodies with weaker hanging walls, but retaining the advantages of the stoping method. In this method, open stopes have the approximate dimensions 40 m-high x 50 m-long, <strong>and</strong> the orebody width up to 30 m. Pillars up to 10 m-thick are left between every stope to support the hanging wall, so some 16% of the ore is utilized as pillars. After the first stope underground mining methods 53
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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 and 28: Principles of raise boring efficien
- Page 29 and 30: Typical operating installation of t
- 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: This joint development process star
- 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
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to the hanging wall. The fill used
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MelBOurne, auSTralia High speed hau
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The Minetruck MT5010 exits from the
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geology The Olympic Dam mineral dep
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Activity Overview Mucking Overview
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on site. Later stopes, which are no
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improved results at Meishan iron or
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ig, six hours/shift, two shifts/day
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Mechanized mining in low headroom a
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large scale copper mining adapted t
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tricky, because the pillars in the
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gerMany/SOuTH kOrea underground min
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which are spread over 10-130 Mpa. A
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CaMPO FOrMOSO, Brazil Sub level cav
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Slot drilling at Ferbasa: The Simba
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getting the best for Peñoles Speci
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They went from drilling 20 m downwa
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keeping a low profile at Panasqueir
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Boomer S1 L drill rig in operation.
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