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This material is intended for use in lectures, presentations and as
handouts to students, and is provided in Power point f...
Outline of Topic 6:
 Introduction
 Application of Cut-and-Fill (C & F) stoping
 The activity cycle of the (C & F) metho...
Introduction
Method in which ore is removed at horizontal slices generally upwards. The ore is
drilled, blown up and remov...
Introduction
 It is one of the more popular methods used for vein deposits and has recently grown in use.
 It is an expe...
Figure showing cut and fill mining method.
Remove ore in horizontal slices, starting
from a bottom undercut and advancing
...
 Because the method involves moving fill material as well as a significant amount of drilling and
blasting, it is relativ...
Application of Cut-and-Fill (C & F) stoping
The C & F method is required when:
 Ore Zones are irregular in shape and orie...
The C & F method
In mining C & F generally upward (overhand)
advances; there is a least common variant -
C & F underhand -...
overhand C & F
Prof. Dr. H.Z. Harraz Presentation
Cut & Fill stoping
9
a) drill-blast of a horizontal slice of ore, typically with
three or four feet thick, removed the roof of the
stope;
b) lo...
Stages of the production cycle of the C & F method :
Prof. Dr. H.Z. Harraz Presentation
Cut & Fill stoping
11
The workers perform all the activities of the production
cycle in the newly opened roof of stope. So, for the
method to be...
Control ceiling by cable bolts :
Sequence of use :
Prof. Dr. H.Z. Harraz Presentation
Cut & Fill stoping
13
C & F method is versatile (there are
different configurations of extraction)
applied to bodies of different
geometries (sh...
Sequences of extracting ore bodies ...
View topic in 3.4.2 : Underground Mining Methods: engineering fundamentals
and inte...
C & F with overhand stopes separated by vertical pillars,
in this case made ​​with backfill:
Prof. Dr. H.Z. Harraz Present...
C & F overhand with ramp and stope access
orepass located in the footwall:
Prof. Dr. H.Z. Harraz Presentation
Cut & Fill s...
The method applies to deposits with dipping 35o to 90o, in
deep or shallow bodies. Stopes may have a width
ranging from 4 ...
Different geometries of
openings in thick ore
bodies (seen in
section).
Prof. Dr. H.Z. Harraz Presentation
Cut & Fill stop...
Fig 1
Narrow body being mined: plan view (left) And
section (right).
Prof. Dr. H.Z. Harraz Presentation
Cut & Fill stoping...
The C & F is a laborious method, requiring high value for the in situ ore. Some dilution
is expected, which occurs when th...
Variant of the C & F: Avoca method
Prof. Dr. H.Z. Harraz Presentation
Cut & Fill stoping
22
Filling in C & F Method
About filling of stopes:
 filling is done during the production cycle (and not after complete
eva...
Filler Models
Prof. Dr. H.Z. Harraz Presentation
Cut & Fill stoping
24
Filling
Functions of filler:
 -preserve access to the stope;
 avoid dilution of ore;
 avoid subsidence on the surface;
...
Types of fillers
 Additional information on "backfill": read articles
 Underground Mining Methods: engineering fundament...
Types of fillers
1) Hydraulic fill (also
called slurry or sand fill)
3) Rock Fill
2) Paste fill
Prof. Dr. H.Z. Harraz Pres...
Advantages of the method
 It is a versatile method and can be adapted to the ore bodies from
any geometrical shape
 Inve...
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Cut and Fill Stoping

Introduction; Application of Cut-and-Fill (C & F) stoping; The activity cycle of the (C & F) method; Stages of the production cycle of the C & F method; Sequences of extracting ore bodies; Filling in C & F Method; About filling of stopes; Functions of filler; Types of fillers; Advantages and disadvantages of the C & F method

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Cut and Fill Stoping

  1. 1. This material is intended for use in lectures, presentations and as handouts to students, and is provided in Power point format so as to allow customization for the individual needs of course instructors. Permission of the author and publisher is required for any other usage. Please see hharraz2006@yahoo.com for contact details. Topic 6: Underground Mining Methods  Cut-and-Fill stoping Hassan Z. Harraz hharraz2006@yahoo.com 2014- 2015
  2. 2. Outline of Topic 6:  Introduction  Application of Cut-and-Fill (C & F) stoping  The activity cycle of the (C & F) method  Stages of the production cycle of the C & F method  Sequences of extracting ore bodies  Filling in C & F Method  About filling of stopes  Functions of filler  Types of fillers  Advantages and disadvantages of the C & F method Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 2 We will explore all of the above in Topic 6.
  3. 3. Introduction Method in which ore is removed at horizontal slices generally upwards. The ore is drilled, blown up and removed from the stope. The resulting empty after the ore to be removed, is filled with a filler ("backfill"). The filler serves as a support for the sides of the stope, and as a platform for the devices when the next slice is mined. It is a recommended method, for example, where iron ore and / or waste are slightly relevant, which restricts the size of underground excavations and allows little time between the removal and the deposition of the mineral filler. Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 3
  4. 4. Introduction  It is one of the more popular methods used for vein deposits and has recently grown in use.  It is an expensive but selective mining method, with low ore loss and dilution.[3] (i.e., allows selective mining and avoid mining of waste or low grade ore).  Is relatively expensive and therefore is done only in high grade mineralization (Because the method involves moving fill material as well as a significant amount of drilling and blasting).  It is a method of shorthole mining used in steeply dipping or It is preferred for orebodies with irregular ore zones and scattered mineralization.  It requires working at face (which is less safe than longhole stoping).  It is used:-  in mining steeply dipping orebodies in stable rock masses (primarily in steeply dipping metal deposits),  in strata with good to moderate stability, and comparatively high grade mineralization.  either fill option may be consolidated with concrete, or left unconsolidated.  Generally uses no cement  Bottom up mining method: Remove ore in horizontal slices, starting from a bottom undercut and advancing upward.  Moderate production rates.  Good resource usage.  Not stress friendly.  Moderate ground support  Ore is drilled, blasted and removed from stope.  The ore is mined in slices: As each horizontal or slightly inclined slice is taken, the voids (Opens) are backfilled with a variety of fill types to support the walls (i.e., the fill can be rock waste, tailings, cemented tailings, or other suitable materials). {(note: The fill serves both to support the stope walls and provide a working platform for equipment when the next slice is mined)}.
  5. 5. Figure showing cut and fill mining method. Remove ore in horizontal slices, starting from a bottom undercut and advancing upward. As each horizontal slice is taken, the voids (Opens) are filled with a variety of fill types to support the walls. (i.e., the fill can be rock waste, tailings, cemented tailings, or other suitable materials). Ore is drilled, blasted and removed from stope Introduction
  6. 6.  Because the method involves moving fill material as well as a significant amount of drilling and blasting, it is relatively expensive and therefore is done only in high grade mineralization where there is a need to be selective and avoid mining of waste or low grade ore.  It is practiced both in the overhand (upward) and in the underhand (downward) directions. i) Overhand (upward) cut and fill o is applied to ore lies underneath the working area and the roof is backfill. o involves a work area of cemented backfill while mining ore from the roof. ii) Underhand (Downward) cut and fill ore o is applied to ore lies beneath the working area and the roof is cemented backfill. o ore overlies the working area and the machines work on backfill. Note: Drift and Fill is similar to cut and fill, except it is used in ore zones which are wider than the method of drifting will allow to be mined. In this case the first drift is developed in the ore, and is backfilled using consolidated fill. The second drift is driven adjacent to the first drift. This carries on until the ore zone is mined out to its full width, at which time the second cut is started atop of the first cut. Introduction
  7. 7. Application of Cut-and-Fill (C & F) stoping The C & F method is required when:  Ore Zones are irregular in shape and orientation.  Ore Is high grade and dilution control is critical.  The Need contacts between ore and waste are structurally critical but not readily visible.  The Waste rock is weak.  Ore Zones are large, but Their rock quality is weak.  Localized Underground stability is required.  Surface Disturbance must be minimized.  The Value of the ore makes recovery of economically viable support pillars.  The Reduction of surface waste storage is important.  The Need exists to advance the working platform for the upward mining of the ore body. Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 7
  8. 8. The C & F method In mining C & F generally upward (overhand) advances; there is a least common variant - C & F underhand - where the feed is from the top down. C & F advancing bottom up  Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 8
  9. 9. overhand C & F Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 9
  10. 10. a) drill-blast of a horizontal slice of ore, typically with three or four feet thick, removed the roof of the stope; b) loading and transport of ore, mechanically removed from the stope for orepass, and then to a lower horizon of transportation; c) removal of loose fragments ("cuttlefish") by the detonation and placement support / reinforcement ceiling; d) filling the floor of the stope (backfilling) with a layer of composite material varied and equal in thickness ore disassembled ceiling. The activity cycle of the C & F method involves the following steps: Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 10
  11. 11. Stages of the production cycle of the C & F method : Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 11
  12. 12. The workers perform all the activities of the production cycle in the newly opened roof of stope. So, for the method to be successful, one must control the behavior of the rock on the outskirts of the stope. This is done in several ways: by controlling the dismantling of the roof, using reinforcement / support for openings and using the stope backfill. Use of roof bolts in C & F Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 12
  13. 13. Control ceiling by cable bolts : Sequence of use : Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 13
  14. 14. C & F method is versatile (there are different configurations of extraction) applied to bodies of different geometries (shafts, inclined tabular or massive deposits) can be divided into separated by vertical pillars and horizontal blocks. Horizontal Pillar (i.e, Floor pillar) separating stopes  Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 14
  15. 15. Sequences of extracting ore bodies ... View topic in 3.4.2 : Underground Mining Methods: engineering fundamentals and international case studies. W.Hustrulid, R.Bullock, SME, 2001. Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 15
  16. 16. C & F with overhand stopes separated by vertical pillars, in this case made ​​with backfill: Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 16
  17. 17. C & F overhand with ramp and stope access orepass located in the footwall: Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 17
  18. 18. The method applies to deposits with dipping 35o to 90o, in deep or shallow bodies. Stopes may have a width ranging from 4 to 40 m. The filler allows to work in the presence of enclosing a low resistance. The ore should, however, have moderate resistance to high. Thick body being mined in plan and in section  Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 18
  19. 19. Different geometries of openings in thick ore bodies (seen in section). Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 19
  20. 20. Fig 1 Narrow body being mined: plan view (left) And section (right). Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 20
  21. 21. The C & F is a laborious method, requiring high value for the in situ ore. Some dilution is expected, which occurs when the backfill is loaded with ore in the stope (usually done by loading LHD's). Moreover, the method provides selectivity and flexibility, allowing good control of ore contents and disposal in the stope, sterile material. Also allows to follow irregular bodies during mining, due to the high degree of selectivity of the drill-blast sequence There are several benefits from an environmental standpoint, using the backfill. The integrity of the host rocks allows less affect the hydrogeology of the mined area. The possibility of subsidence at the surface is quite limited. Reduce the tailings storage areas on the surface because they can be taken back to the stopes, as backfill Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 21
  22. 22. Variant of the C & F: Avoca method Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 22
  23. 23. Filling in C & F Method About filling of stopes:  filling is done during the production cycle (and not after complete evacuation of the stope, as in SLS);  Hydraulic filling (water and sand particle size = hydraulic sand-fill) is the most common, containing 60 to 70% solids and requiring deposition techniques and special drain;  the filling with hydraulic sand-fill, the distribution for the stopes is done by piping;  The stope is filled almost to the ceiling height;  backfill needs to be the strongest, is added to the cement mixture;  When the water is drained, a good base for moving mining equipment while it is formed in the upper slice stope;  the backfill, traffic person is prevented for a few hours and the vehicle for several days. Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 23
  24. 24. Filler Models Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 24
  25. 25. Filling Functions of filler:  -preserve access to the stope;  avoid dilution of ore;  avoid subsidence on the surface;  serve as a working platform for workers in mining the next horizontal slice; The time of placing the backfill is critical because it must take the original load was exerted on the ore. Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 25
  26. 26. Types of fillers  Additional information on "backfill": read articles  Underground Mining Methods: engineering fundamentals and international case studies. W.Hustrulid, R.Bullock, SME, 2001, cap. 69. Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 26
  27. 27. Types of fillers 1) Hydraulic fill (also called slurry or sand fill) 3) Rock Fill 2) Paste fill Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 27
  28. 28. Advantages of the method  It is a versatile method and can be adapted to the ore bodies from any geometrical shape  Investments are moderated to implement the method  minimizes subsidence  High recovery and low dilution (selective method)  Waste can be taken to the basement, avoiding surface contamination  Due to the high cost of mining, is only applicable in ores of high value;  Requires hand labour intensive and more specialized;  The activity of filling complicates the production cycle, causing reduction in production;  There are risks of instability in mass if the backfill is not properly sized and applied. Disadvantages Prof. Dr. H.Z. Harraz Presentation Cut & Fill stoping 28

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