CA1231106A - Excavation and method of excavation - Google Patents
Excavation and method of excavationInfo
- Publication number
- CA1231106A CA1231106A CA000469428A CA469428A CA1231106A CA 1231106 A CA1231106 A CA 1231106A CA 000469428 A CA000469428 A CA 000469428A CA 469428 A CA469428 A CA 469428A CA 1231106 A CA1231106 A CA 1231106A
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- Canada
- Prior art keywords
- tunnels
- series
- set forth
- excavation
- level
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C41/00—Methods of underground or surface mining; Layouts therefor
Abstract
ABSTRACT
The excavation and method of excavation of the present invention reduces the risk and the amount of structural support necessary in undercut-and-fill excavations while increasing the strength of such excavation. A decline is excavated and a first series of spaced tunnels is driven in a first direction at a first level. The first series of tunnels is then provided with a substantial layer of high strength material such as concrete, to form a first series of monolithic reinforcement beams, the space above being then backfilled to the roof with support material. A second series of tunnels is then driven between the filled first series of tunnels. The second series of tunnels is then provided with a like layer of concrete to form reinforcement beams contiguous with the first series of beams, and then backfilled with support material. A third series of spaced tunnels is then driven in a second direction at a second level of the decline, the second direction being transverse to the first direction. The tunnels of the third series are then reinforced and filled and a fourth series of tunnels is then driven between the tunnels of the third series, reinforced and subsequently filled. This is repeated at lower levels, in each case the direction of the tunnels being transverse to the direction of the tunnels of the level immediately above. A cross-wise lattice of supporting beams is thus created by the reinforcement beam operations. This lattice protects the tunnels beneath it so as to allow wide excavations with minimal structural bracing and controls the amount of unprotected opening at each stage of the operation.
The excavation and method of excavation of the present invention reduces the risk and the amount of structural support necessary in undercut-and-fill excavations while increasing the strength of such excavation. A decline is excavated and a first series of spaced tunnels is driven in a first direction at a first level. The first series of tunnels is then provided with a substantial layer of high strength material such as concrete, to form a first series of monolithic reinforcement beams, the space above being then backfilled to the roof with support material. A second series of tunnels is then driven between the filled first series of tunnels. The second series of tunnels is then provided with a like layer of concrete to form reinforcement beams contiguous with the first series of beams, and then backfilled with support material. A third series of spaced tunnels is then driven in a second direction at a second level of the decline, the second direction being transverse to the first direction. The tunnels of the third series are then reinforced and filled and a fourth series of tunnels is then driven between the tunnels of the third series, reinforced and subsequently filled. This is repeated at lower levels, in each case the direction of the tunnels being transverse to the direction of the tunnels of the level immediately above. A cross-wise lattice of supporting beams is thus created by the reinforcement beam operations. This lattice protects the tunnels beneath it so as to allow wide excavations with minimal structural bracing and controls the amount of unprotected opening at each stage of the operation.
Description
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SPECIFICS
The present invention relates to a method of excavation and to an excavation. The excavation and method of the present invention has particular application to mines and methods of mining.
The general concept of undercut and fill mining has been known and used for many years. Such mining has been effected for the most part in ore bodies which are tabular at an angle to the horizontal. Vertical or diagonal decline tunnels have been placed beside the ore body enabling lateral mining of the ore body. At each progressively lower level of the ore body, an entire "room" is opened with access to the decline tunnel. The room must, of necessity, be braced and supported to prevent collapse of the overlying portion of the back fill and soil above the room, which back fill and soil may become unstable by the sloping of ore from the room. Depending on the size of the room and the depth and weight of the overburden, the bracing and structural supporting system may be wood, steel, concrete or any other suitable structural material or combination of them. The erection or removal of the structural support system generally adds significant time and cost to the project. Further, regardless of the strength of the structural system, the very fact that the overburden is unstable adds to the inherent danger in the excavation and mining operation.
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Once all of the extractable ore has been taken from the room at a given level, the room is back filled. Generally, the fill material is comprised of low strength, cemented, hydraulically placed tailings. The filling operation results in a low strength, brittle, block of fill having little shear strength. Overburden stress is therefore readily transferred through the block rather than contained by it. As a room at the next level down is opened for excavation, the stress, and hence the instability of the overburden is increased, necessitating increased structural bracing and support, adding to the inherent danger. As the mining operation descends sequentially from one level to the next lower level, the mass of unstable overburden, and hence the risks, the structural support necessary and the time necessary to erect and dismantle the support, all increase.
The excavation and method of excavation of the present invention reduces some of the disadvantages of the aforementioned traditional methods and excavations made thereby. The present invention is based on the well known principle of load shedding in the vertical direction.
However, the present invention accomplished this through the action of a series of separate monolithic beams of relatively narrow width which are generally parallel and typically made of concrete. Multi-strength and multi-media bulk back fill is used between the beams to reduce the cost and soften the fill.
C As level after level of the ore is mined and subsequently I
beam-reinforced, a cross-wise lattice-work of beams is developed; the method of the present invention reduces the risk inherent in any excavation operation and minimizes the structural support necessary at each level and the time necessary to erect and dismantle the structural support, while strengthening the strata support around the excavation.
Although particularly suited for mining, the method of the present invention may be used for any type of excavation.
The present invention relates to both an excavation and a method of excavation. The excavation structure disclosed in the present invention can be, but need not be produced by the presently disclosed method of excavation of the invention.
In one aspect of the invention the equation comprises a decline and a series of spaced tunnels connected to the decline.
In another aspect of the invention, the excavation comprises a decline and a first series of spaced tunnels connected to the decline, the tunnels being filled with support material comprising beam reinforcement and backfill. A second series of tunnels is then opened in contiguous relation between the filled tunnels of the first series, to complete the excavation of that portion of the level, which second tunnel series is then beam reinforced and backfilled.
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A third series of spaced tunnels is then excavated at the next underlying level, being laterally inclined in a second direction, and connected to the decline at a second level. The second direction is laterally transverse to the first direction. These tunnels then are filled with support material, being beam reinforced in like fashion to the preceding series of overlying tunnels, and then backfilled.
A fourth series of tunnels is excavated between the tunnels of the third series, beam reinforced, and backfilled.
The process is then repeated at succeeding underlying levels, resulting in a fifth series of spaced tunnels extending in a third lateral direction and connected to the decline at a third level, the third direction being transverse to the second direction. This fifth series of tunnels is similarly filled with support material.
Excavation of the third level is then completed by excavating a sixth series of tunnels located between the tunnels of the fifth series, which sixth series is then reinforced and subsequently backfilled to the overlying concrete roof.
At the next lower level, the fourth level, a series of spaced tunnels is laterally directed in a fourth direction other than that of at least the two overlying levels, and connected to the decline at the fourth level.
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In an eighth tunnel series aspect of the invention, the excavation is as described in the previous paragraph and further comprises an eighth series of tunnels between the seventh series of tunnels, which are similarly filled with support material.
The tunnels herein referred to are considered as being horizontally directed. They may in fact be inclined, due to the formation and other circumstances; at angles of inclination permitting excavation thereof by mechanized equipment.
The tunnels of succeeding underlying levels are laterally inclined from the immediately overlying level, located above, the immediately overlying level being laterally inclined from the preceding level.
The first and second series of tunnels are connected to the decline by a first connecting passage. The third and fourth series of tunnels are connected to the decline by a second connecting passage. The fifth and sixth series of tunnels are connected to the decline by a third connecting passage. The seventh and eighth series of tunnels are connected to the decline by a fourth connecting passage. The second connecting passage does not underlay the first connecting passage, being horizontally offset from the first passage. The third passage is similarly horizontally offset from the second connecting passage. The connecting passages are preferably horizontal.
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The first series of tunnels at each level are generally of substantially Equal width. The spacing between these first series tunnels at each level may be substantially equal to or greater than the widths of the tunnels. The second series of tunnels at each level generally are equal in width to the spacing between the first series tunnels. Thus, the excavation of each level it completed by the second series of tunnel excavations for that level.
The support material typically initially filling an excavated, reinforced and backfilled tunnel comprises à layer of previous material, a layer of impervious material, a structural layer and optionally a layer of bulk fill. The previous material is preferably unconsolidated, and may be sand. The layer of impervious material is laid above the layer of previous material and comprises plastic. The structural layer which is preferably concrete but may include other structural material, such as steel or other metals, is deposited upon the layer of impervious material. If metal plate is used, it may serve as both the impervious and structural layers. The layer of bulk fill is backfilled above the concrete layer. The bulk fill may be low-strength cemented sand or uncemented sand.
In another aspect of the invention, the excavation comprises a decline and a first series of spaced tunnels of substantially equal widths extending parallel to one another in a first substantially horizontal passage at a first level. The spacing between adjacent tunnels is substantially equal to or greater than the widths of the tunnels.
In a subsequent aspect of the invention, the first series of tunnels is filled with support material. A second series of tunnels is driven between the filled first series of tunnels, the tunnels of the second series being connected to the decline by the first passage.
In a subsequent aspect of the invention, the second series of tunnels and the first passage are filled with support material. A third series of spaced tunnels of substantially equal widths extends parallel to one another in a second horizontal direction and is connected to the decline by a second horizontal passage at a second, lower level. The second direction is transverse to the first direction and the spacing between adjacent tunnels of the third series is substantially equal to or greater than the tunnel widths.
In a subsequent aspect of the invention, the third series of tunnels is filled with support material. A fourth series of tunnels is driven between the filled third series of tunnels, the tunnels of the fourth series being connected to the decline by the second passage.
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In a subsequent aspect of the invention, the fourth series of tunnels and the second passage are filled with support material. A fifth series of spaced tunnels of substantially equal widths extends parallel to one another in a third horizontally passage at a third level. The third direction also may be transverse to the first direction. The spacing between adjacent tunnels is substantially equal to or greater than the widths of adjacent tunnels.
In a subsequent aspect of the invention, the fifth series of tunnels is filled with support material. A sixth series of tunnels is located between the filled fifth series of tunnels, the tunnels of the sixth series being connected to the decline by the third passage.
In a subsequent aspect of the invention, the sixth series of tunnels and the third passage are filled with support material. A seventh series of spaced tunnels extends parallel to one another in a fourth horizontal direction and is connected to the decline by a fourth horizontal passage at a fourth level. The fourth direction is transverse to the third direction. The fourth direction generally would be transverse to the second direction. The spacing between adjacent tunnels is substantially equal to or greater than the widths of the adjacent tunnels.
go ~311~?6 g In a subsequent aspect of the invention, the seventh series of tunnels it filled with support material. An eighth series of tunnels is located between the filled seventh series of tunnels, the tunnels of the eighth series being connected to the decline by the fourth passage.
Relative lateral inclinations of the tunnels at descending levels may be selected so as to provide repeating, progressive directional sequences, reoccurring each three or four levels, so as to provide in effect, a vertically superimposed lattice work of laterally inclined beams.
The method of excavation of the present invention comprises excavating a decline and then driving a first series of spaced tunnels in a first direction at a first level of the decline. The first series of tunnels would then be filled with support material. A second series of tunnels would then be driven between the filled tunnels of the first series.
In selecting angles of lateral inclination of the tunnels at descending levels of the excavation care is taken that the overlying beam support structures, which in effect constitute the roof portions for the immediately underlying tunnels in area of excavation, extend generally transversely of the tunnels, so as to limit the unsupported span of the respective beam structures until such time as the respective I
tunnels are backfilled into potential load supporting relation with the superposed beams.
The tunnels of the second series would then normally be filled with support material and a third series of spaced tunnels may then be driven in a second direction from a second level of the decline, the second direction being laterally transverse to the first direction. The tunnels of the third series would then be filled with support material and a fourth series of tunnels then driven between the filled tunnels of the third series.
The tunnels of the fourth series may be filled with support material and a fifth and succeeding series of spaced tunnels then driven in a predetermined changed directions at respective deeper levels of the decline.
In carrying out the presently disclosed method of excavation a succeeding series of tunnels, excavated at a given level normally utilize a common connecting passage to access the decline, from which access passage the tunnels extend, often from both sides of the passage, by virtue of its location intermediately of the area encompassed by the respective level.
The present invention thus provides, in the excavation of a level, being one of a number of proposed descending levels .
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of excavation, the subject level extending laterally from adjacent a decline passage, being accessed therefrom by a connecting passage, wherein a first plurality of generally parallel, mutually spaced apart tunnels extend at a predetermined angle of lateral inclination from the connecting passage, the improvement comprising a plurality of separate, first monolithic beams within the tunnels, Mach being in load transfer relation with an underlying layer and having fill in load transfer, strata stabilizing relation deposited thereon, to substantially backfill the excavation above the beams.
There is further provided at that level a plurality of second tunnels each extending laterally contiguously between adjacent tunnels of the first plurality of tunnels, the second tunnels each having therein a monolithic second beam substantially contiguous with adjacent ones of the first plurality of monolithic beams.
The second tunnels have fill deposited on the beams to fill the excavation there above.
In the preferred embodiment the subject monolithic beams comprise a concrete layer extending widths and along substantially the length of the respective tunnel. The concrete of the beams may include reinforcement elements therein, depending upon the anticipated load requirements in the respective strata.
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In order to facilitate the construction of the beams and to ensure optimum utilization of them, a layer of substantially unconsolidated material such as sand is generally deposited in the base of the tunnels, over which an impermeable layer, such as a layer of plastic is laid, to form a bed for the respective beam, onto which it is poured. Furthermore, during tunnellin~ of the succeeding level there beneath, the sand layer protects the beam by permitting safe undercutting in relation thereto, so that generally the sand falls away and is removed.
While being influenced, dimensionally, by the nature of the material being excavated, in a fully mechanized operation the tunnels of the initial series, at any one level would be size limited, particularly laterally to a range of abut three to five metros, to satisfy equipment and operational requirements; in particular to reduce the requirement for structural bracing and reinforcement, while the subsequent loaded stress levels of the concrete beams placed in the tunnels also are limited. Tunnel heights are generally about three metros or greater, primarily to satisfy equipment and operational requirements.
In the preferred mode, the initial unconsolidated layer such as sand, typically about one half moire thick has an impervious plastic sheet laid there over, to serve as a diaphragm Jo "I
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both in the pouring of the concrete, to facilitate the curing thereof, and to assist in containment of the hydraulically placed back fill layers there above.
The preferred concrete beams generally comprise a layer of one to one and a half metros thick, typically of 3000 pounds per square inch concrete, poured onto the plastic and contained laterally by toe walls of the tunnel. Reinforcement for the concrete may be introduced, if structurally required.
Alternatively structural metal, such as steel, may be used. If metal plate of substantial area covering form is used, it may serve as the impervious layer.
Is is contemplated that the efficient utilization of the reinforcement concrete may be enhanced by suitably profiling the upper surface of the underlying sand layer, along the length of the respective tunnel, to thereby form to a desired configuration the undersurface of the beam so formed.
In the driving of the underlying tunnels in the succeeding level, as a for-instance, the succeeding beams encountered could provide sequential barrel-vau]ted roof portions. It is recognized that certain consequences could flow, in regard to back filling of such transverse, barrel-vaulted roof which might diminish the accrued advantage of such structural improvement.
These various aspect of the invention may be repeated in sequence to the lowest level of the excavation as desired.
The excavation and method of excavation of the present invention will be described with reference to a method of mining and a mine, a preferred embodiment of which is illustrated in the drawings, wherein:
Figure 1 is an exploded series of time sequential isometric views of three levels of an ore body, each of which have been partially subject to the excavation of the present invention;
Figure 2 is a plan view of the upper level shown in Figure 1, with a plan view of the underlying and subsequent middle level of Figure 1 being shown in dashed form;
Figure 3 is a plan view of the middle level of Figure 1, with a plan view of the underlying and subsequent lower level of Figure 1 being shown in dashed form;
Figure 4 is a plan view of the lower level of Figure l; and Figure 5 is a time lapsed sequential section taken along lines 5-5 in Figures 1, 2, 3 and 4 at respective times when the subject level which those Figures illustrate had been I, ~Z3~
driven, reinforced and backfilled, but prior to drilling of the succeeding, lower level.
Referring first to Figure 1, it represents three slabs or levels of a geological body, 10 exploded for ease of reference and shown at sequential time intervals. An upper slab, 12 lies above a middle slab, 14 which, in turn, lies above a lower slab, 16. Relative to the other slabs, the upper slab, 12 is shown at the earliest time interval. As the preferred embodiment will be described and illustrated with reference to mining operations and the mine illustrated, it will be assumed that the geological body, 10 is beneath the earths surface, which is not shown, and is, in part, an ore body. However, the present invention may be used in connection with any load bearing material such as rock, soil or sand.
Ore bodies are generally tabular and lie at a random angle to the surface. Access to the ore body may he made by a sloped decline tunnel from the surface at the edge of the ore body. The decline typically may be a conventional trackless passage. The decline typically enables removal of the excavated material from the excavation, in this case mined ore, and supply of fill material. In Figure 1, a portion of the decline, 18 is shown in each slab. However, the decline, 18 is continuous from the surface to the lowest level of the excavation. The decline is located in that portion of the slab where there is no ore to be mined.
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After at least a portion of the decline, 18 is excavated, a first access passage, 24 is provided, and a series of spaced tunnels, 20 is driven in a first direction, 22 at the first level, 12 of the decline, 18. The tunnels of the first series, 20, shown in plan view in Figure 2, are parallel to each other and driven in a horizontal plane. They are connected to the decline by the horizontal passage, 24. The tunnels of the first series, 20 are of substantially equal widths w and the spacing S between adjacent tunnels of the lo first series, 20 is substantially equal to or greater than the widths W of adjacent tunnels, 20.
The widths of the tunnel are determined by, among other factors, the material through which they are drilled.
Typically the widths of the tunnels are between three I and five (5) metros to satisfy equipment and operational requirements. By thus keeping the widths of the tunnels, 20 relatively narrow, the requirement for structural bracing and reinforcement is reduced and the concrete beams to be placed in the tunnels during subsequent filling operations are kept from being over stressed. Typically the heights H of the tunnels are about three (3) metros or greater to satisfy equipment and operational requirements. While the tunnels and the horizontal passages described and illustrated are typically horizontal, they may be sloped at an angle which can he negotiated by a tracked vehicle I
It is after this step of the method that the excavation is illustrated in -the upper slab, I of Figure 1 and in Figure 2. At this stage, the excavation comprises the decline, lo and a first series of spaced horizontal tunnels, 20 connected to the decline, 18 ho a first horizontal passage, 24.
The first series of tunnels, 20 are then filled with support material. This phase, represented in Figure 5 of the drawings, enables the void left by thy tunneling to be filled in order to structurally stabilize the ore body, 10. Although the tunnels of the first series, 20 are filled, the first horizontal passage, 24 is not filled at this stage.
The support material, shown in Figure 5 is a Tim elapse cross section of all three levels of Figure 1 showing the entire series of excavation, reinforcement and back fill for the illustrated three levels when respectively completed. It generally comprises a layer of previous unconsolidated material, 26, which subsequently generally falls into the succeeding, lower level during the driving thereof), a layer of impervious material, 28, a structural layer of load bearing material, 30 and a layer of bulk fill, 32. The previous material, 26 is typically a half (1~2) moire layer of sand plastic may be used as the impervious layer, 28. Preferably, the load bearing material is concrete. However structural metal such as steel may be used. If metal plate is used, it I
may serve as both the impervious end structural layers. A one (1) to one and a half (1 1i2~ moire layer of concrete is typical, although the exact thickness will be determined by the span adopted for the underlying tunnels. The widths of crossing tunnels in the levels above and below will determine whether or not reinforcement of the concrete is required. The bulk fill layer, I may be low strength cemented sand or uncemented sand. In the embodiment shown in the bottom level of Figure 5, the bulk fill, 32 lies above the concrete, 30, which lies above the plastic, 28, which, in turn, sits on the previous sand layer, 26. The various layers act as fill layers, while the structural concrete layer acts also as a beam to shed the load of the levels above. The initial presence of the unconsolidated layer, 26 enables drilling of tunnels in the layer beneath without any damage to the structural layer, which structural layer then forms the roof for the succeeding, underlying tunnels.
A second series of tunnels snot shown in the drawings is then driven in the spaces, 34 between the filled tunnels of the first series, 20. Because the tunnels of the first series, 20 are parallel and of equal widths and are illustrated as being equally spaced, the tunnels of the second series, 34 will be likewise. At this stave of the operation, the excavation comprises a decline, 18 and a first series of spaced tunnels, 20 connected to the decline, 18, the tunnels of the first I
lug --series, 20 being filled with support material, and a second series of tunnels, 34 between the filled tunnels of the first series, 20. It will be understood that size of the tunnels, 34 of the second series will equal the spacing between the tunnels, 20, and may well exceed the size of the tunnels, 20.
The tunnels of the second series t34) and optionally the first horizontal connecting passage, 24 are then filled with support material. The decline, 18 is then further extended to the next level, 14 of the excavation. A third lo series of spaced tunnels, 36 is then driven in a second laterally oriented direction, 38, the second direction, 38 being transverse to the first laterally oriented direction, 22. By driving the third series of tunnels, 36 in the second direction, 38, the third series of tunnels underlie and are traversed by the hems former by the reinforcement of the tunnels, 20 of the first level and tunnels ~34) of the second series above. The lateral orientation Al relation between the tunnels, 36 of the third series and those of the first level, 12 there above may be seen from Figure 2, where the dash lines represent the second level, 14 after drilling of the third series of the tunnels, 36.
The horizontal tunnels of the third series, 36 are connected to the decline, 18 by the second horizontal passage, 40. The tunnels of the third series, 36 are of substantially ~.~
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equal widths W and the spacing S between adjacent tunnels of the third series, 36 is shown to be substantially equal to, but could well be greater than the widths of adjacent tunnels, 36.
At this stage of the operation, illustrated by the middle slab, 14 of Figure 1 and by Figure 3, the excavation comprises a decline, 18 and a first series of spaced tunnels, 20 in a first direction, 22, the tunnels, 20 being connected to the decline, 18 at a first level, 12 and filled with support material. A second series of tunnels, 34 is between the tunnels of the first series, 20, the tunnels of the second series, 36 being filled ilk support material. A third series of spaced tunnels, 36 is in a second direction, 38 and is connected to the decline, 18 by a second horizontal passage, 40 at a second level, 14. The second direction, 38 is transverse to the first direction, 22.
The tunnels of the third series, 36 are then filled with support material and a fourth series of tunnels, 42 is then driven between the filled tunnels of the third series, 36. The relation between the tunnels of the fourth series, 42 to those of the third series, 36 is analogous to the relation between the tunnels of the second series, 34 and those of the first series, 20. In other words, the tunnels of the fourth series, 42 are parallel and of substantially equal widths W and the spacing S between adjacent tunnels of the fourth series, 42 lo 3 by is substantially equal to or greater than to the widths of the adjacent tunnels, 42.
At this stage of the operation, which is not illustrated, the excavation comprises a decline, 18 and a first series of spaced tunnels, 20 in a first direction, 22, the tunnels of the first series, 20 being connected to the decline, 18 at a first level, 12 by a first horizontal passage, 24 and filled with support material. A second series of tunnels, 34 is between the tunnels of the first series, 20, the tunnels of the second series, 34 and the first horizontal passage, 24 being filled with support material. A third series of spaced tunnels, 36 is in a second direction, 38 and connected to the decline, 18 at a second level, 14 by a second horizontal passage, 40, the second direction, 38 being transverse to the first direction, 22 and the tunnels of the third series, 36 being filled with support material. A fourth series of tunnels, 42 is between the tunnels of the third series, 36.
The tunnels of the fourth series, 42 and the second horizontal passage, 40 are then filled with support material.
A fifth series of spaced tunnels, 44 is driven in a third direction, 46 at a third level, 16 of the decline, 18 by a third horizontal passage, 48. The third direction, 46 is transverse to the first direction, 22.
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An alternate fifth series of spaced tunnels, 50 may be driven in an alternate third direction, 52 at the third level, 16 of the decline, 18, the tunnels of the alternate fifth series, 50 being connected to the decline by the third horizontal passage, 43. The alternate third direction, 52 is transverse to both the first, 22 and second, 38 directions.
The relative transverse directions of adjoining levels creates a cross-wise lattice-work of beams as level after level of the ore body, 10 is excavated and subsequently filled.
As was the case for the tunnels, 20 of the first series and tunnels, 36 of the third series, the tunnels, 44 of the fifth series are parallel and of substantially equal widths W; the spacing S between adjacent tunnels, 44 of the fifth series is substantially equal to or greater than the widths w of the tunnels, 44.
At this stage of the operation, which is illustrated by the lower level, slab 16 in Figure 1 and by Figure 4, the excavation comprises a decline, 18 and a first series of spaced tunnels, 20 in a first direction, 22, the tunnels, 20 being Jo connected to the decline, 18 at a first level, 12 by a first horizontal passage, 24 and filled with support maternal. A
second series of tunnels, 34 is driven between the tunnels of the first series, 20, the tunnels of the second series, 34 and optionally the first horizontal passage, 24 being filled with ~Z3~
support material. A third series of spaced tunnels, 36 is in a second direction, 38 and connected to the decline, 18 by a second horizontal passage, 40 at a second level, 14. The second direction, 38 is transverse to the first direction, 22 and the tunnels of the third series, 36 are filled with support material. A fourth series of tunnels, 42 is between the tunnels of the third series, 36, thy tunnels of the fourth series, 42 and optionally the second horizontal passage, 40 being filled with support material. A fifth series of tunnels, 44 or 50 is in a third direction, 46 or 52, respectively and is connected to the decline, 18 by a third horizontal passage, 48 at a third level, 16, the third direction, 46 or 52 being transverse to the second direction and, in some cases, 52 transverse to the first direction, 22.
The tunnels of the fifth series, 44, 50 are then filled with support material. A sixth series of tunnels, 54 is then driven between the filled tunnels of the fifth series, 44, 50. The relation between the tunnels of the sixth series, 54 to whose of the third series, 44, 50 is analogous to those of the first, 20 and second, 34 and to those of the third, 36 and fourth, 42 series. The tunnels of the sixth series, 54 are parallel and of substantially equal widths W, and the spacing S
between adjacent tunnels of the sixth series, 54 is substantially equal to or greater than the widths W of the tunnels.
The tunnels of the sixth series, 54 and optionally the third horizontal passage, 48 are then filled with support material. A seventh series of spaced tunnels, not shown, may be driven in a fourth direction at a fourth level of the decline, 18, the fourth direction being transverse to the third direction, 46 (or 2). The fourth direction may also be transverse to the second direction, 38. The tunnels of the seventh series may be identically laterally oriented to those of the first series of tunnels, 20, by which the lateral orientation pattern of tunnels could repeat every three levels.
The tunnels of the seventh series would then be filled with support material. An eighth series of horizontal tunnels may then be driven between the filled tunnels of the seventh series. The tunnels of the eighth series may correspond in lateral orientation, size and spacing to the tunnels of the second series, 34 in that they are parallel and of substantially equal widths W. The spacing S between adjacent tunnels of the eighth series is substantially equal or greater than the widths of adjacent tunnels. The tunnels of the eighth series are connected to the decline, 18 by a fourth horizontal passage.
The tunnels of the eighth series and the associated fourth horizontal passage are then filled and the next level downward is excavated, in each case the tunnels of each level being transverse to those of the level above.
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The various steps in the method of the invention may be repeated in sequence or otherwise to the lowest level of the excavation.
If it is desirable to retain an open room at any level of the excavation, this can be done by omitting the filling step in respect of selected tunnels. If the room is desired to be of substantial width, the structural reinforcement layer in the tunnels of the level above might be additionally suitably strengthened.
The completed excavation will appear to be similar in make-up for each application of the method, but the number of tunnels being simultaneously driven can vary according to the rock competency. It should be understood that each series of tunnels may be subdivided into sub-series with intermediate filling or that more than one series of tunnels may be drilled at any level if ground conditions permit such an approach.
While the conventional system of hydraulic or pneumatic drilling, blasting and load-haul-dump mucking may be used to excavate, the method of the present invention may be used with tunnel boring machines and similar rock cutting and boring machines. Fill may be placed by a pneumatic blower or by wheeled transportation. Survey control of the operation should be constant and may be effected by the use of a laser ~23~
- 2Ç -system. Ventilation of the excavation may be effected by way of the decline through the horizontal passage at the level hying excavated.
The method of excavation and the excavation of the present invention is particularly suited to the mining of wide ore bodies. It is the width of wide ore bodies that leads to problems in that the excavation becomes less stable as the width increases. The method and form of the excavation disclosed and claimed sheds the load from the roof of any tunnel to the supporting strata below. By using low strength bulk fill between the high strength concrete beams, the fill can absorb pressure instead of transmitting it. By contrast, in the traditional undercut-and-fill system, the fill used is not strong enough to be stable over wide spans. By using a cross-wise lattice, the method and excavation of the present invention reduces the exposed span to a width controlled by engineering decision rather than by the vagaries of the ore body. The strength of the excavation is increased while the risk imposed by the general lack of homogeneity in rock masses is reduced.
While a specific embodiment of the invention has been disclosed and illustrated herein, it is to be understood that variations and modifications are possible without departing ~33~ I
from the spirit or essence of this invention. The method of excavation and the excavation may be applicable to operations other than mining, although the disclosure and drawings are directed to an embodiment in the mining field.
7290b/1-29
SPECIFICS
The present invention relates to a method of excavation and to an excavation. The excavation and method of the present invention has particular application to mines and methods of mining.
The general concept of undercut and fill mining has been known and used for many years. Such mining has been effected for the most part in ore bodies which are tabular at an angle to the horizontal. Vertical or diagonal decline tunnels have been placed beside the ore body enabling lateral mining of the ore body. At each progressively lower level of the ore body, an entire "room" is opened with access to the decline tunnel. The room must, of necessity, be braced and supported to prevent collapse of the overlying portion of the back fill and soil above the room, which back fill and soil may become unstable by the sloping of ore from the room. Depending on the size of the room and the depth and weight of the overburden, the bracing and structural supporting system may be wood, steel, concrete or any other suitable structural material or combination of them. The erection or removal of the structural support system generally adds significant time and cost to the project. Further, regardless of the strength of the structural system, the very fact that the overburden is unstable adds to the inherent danger in the excavation and mining operation.
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Once all of the extractable ore has been taken from the room at a given level, the room is back filled. Generally, the fill material is comprised of low strength, cemented, hydraulically placed tailings. The filling operation results in a low strength, brittle, block of fill having little shear strength. Overburden stress is therefore readily transferred through the block rather than contained by it. As a room at the next level down is opened for excavation, the stress, and hence the instability of the overburden is increased, necessitating increased structural bracing and support, adding to the inherent danger. As the mining operation descends sequentially from one level to the next lower level, the mass of unstable overburden, and hence the risks, the structural support necessary and the time necessary to erect and dismantle the support, all increase.
The excavation and method of excavation of the present invention reduces some of the disadvantages of the aforementioned traditional methods and excavations made thereby. The present invention is based on the well known principle of load shedding in the vertical direction.
However, the present invention accomplished this through the action of a series of separate monolithic beams of relatively narrow width which are generally parallel and typically made of concrete. Multi-strength and multi-media bulk back fill is used between the beams to reduce the cost and soften the fill.
C As level after level of the ore is mined and subsequently I
beam-reinforced, a cross-wise lattice-work of beams is developed; the method of the present invention reduces the risk inherent in any excavation operation and minimizes the structural support necessary at each level and the time necessary to erect and dismantle the structural support, while strengthening the strata support around the excavation.
Although particularly suited for mining, the method of the present invention may be used for any type of excavation.
The present invention relates to both an excavation and a method of excavation. The excavation structure disclosed in the present invention can be, but need not be produced by the presently disclosed method of excavation of the invention.
In one aspect of the invention the equation comprises a decline and a series of spaced tunnels connected to the decline.
In another aspect of the invention, the excavation comprises a decline and a first series of spaced tunnels connected to the decline, the tunnels being filled with support material comprising beam reinforcement and backfill. A second series of tunnels is then opened in contiguous relation between the filled tunnels of the first series, to complete the excavation of that portion of the level, which second tunnel series is then beam reinforced and backfilled.
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A third series of spaced tunnels is then excavated at the next underlying level, being laterally inclined in a second direction, and connected to the decline at a second level. The second direction is laterally transverse to the first direction. These tunnels then are filled with support material, being beam reinforced in like fashion to the preceding series of overlying tunnels, and then backfilled.
A fourth series of tunnels is excavated between the tunnels of the third series, beam reinforced, and backfilled.
The process is then repeated at succeeding underlying levels, resulting in a fifth series of spaced tunnels extending in a third lateral direction and connected to the decline at a third level, the third direction being transverse to the second direction. This fifth series of tunnels is similarly filled with support material.
Excavation of the third level is then completed by excavating a sixth series of tunnels located between the tunnels of the fifth series, which sixth series is then reinforced and subsequently backfilled to the overlying concrete roof.
At the next lower level, the fourth level, a series of spaced tunnels is laterally directed in a fourth direction other than that of at least the two overlying levels, and connected to the decline at the fourth level.
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In an eighth tunnel series aspect of the invention, the excavation is as described in the previous paragraph and further comprises an eighth series of tunnels between the seventh series of tunnels, which are similarly filled with support material.
The tunnels herein referred to are considered as being horizontally directed. They may in fact be inclined, due to the formation and other circumstances; at angles of inclination permitting excavation thereof by mechanized equipment.
The tunnels of succeeding underlying levels are laterally inclined from the immediately overlying level, located above, the immediately overlying level being laterally inclined from the preceding level.
The first and second series of tunnels are connected to the decline by a first connecting passage. The third and fourth series of tunnels are connected to the decline by a second connecting passage. The fifth and sixth series of tunnels are connected to the decline by a third connecting passage. The seventh and eighth series of tunnels are connected to the decline by a fourth connecting passage. The second connecting passage does not underlay the first connecting passage, being horizontally offset from the first passage. The third passage is similarly horizontally offset from the second connecting passage. The connecting passages are preferably horizontal.
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The first series of tunnels at each level are generally of substantially Equal width. The spacing between these first series tunnels at each level may be substantially equal to or greater than the widths of the tunnels. The second series of tunnels at each level generally are equal in width to the spacing between the first series tunnels. Thus, the excavation of each level it completed by the second series of tunnel excavations for that level.
The support material typically initially filling an excavated, reinforced and backfilled tunnel comprises à layer of previous material, a layer of impervious material, a structural layer and optionally a layer of bulk fill. The previous material is preferably unconsolidated, and may be sand. The layer of impervious material is laid above the layer of previous material and comprises plastic. The structural layer which is preferably concrete but may include other structural material, such as steel or other metals, is deposited upon the layer of impervious material. If metal plate is used, it may serve as both the impervious and structural layers. The layer of bulk fill is backfilled above the concrete layer. The bulk fill may be low-strength cemented sand or uncemented sand.
In another aspect of the invention, the excavation comprises a decline and a first series of spaced tunnels of substantially equal widths extending parallel to one another in a first substantially horizontal passage at a first level. The spacing between adjacent tunnels is substantially equal to or greater than the widths of the tunnels.
In a subsequent aspect of the invention, the first series of tunnels is filled with support material. A second series of tunnels is driven between the filled first series of tunnels, the tunnels of the second series being connected to the decline by the first passage.
In a subsequent aspect of the invention, the second series of tunnels and the first passage are filled with support material. A third series of spaced tunnels of substantially equal widths extends parallel to one another in a second horizontal direction and is connected to the decline by a second horizontal passage at a second, lower level. The second direction is transverse to the first direction and the spacing between adjacent tunnels of the third series is substantially equal to or greater than the tunnel widths.
In a subsequent aspect of the invention, the third series of tunnels is filled with support material. A fourth series of tunnels is driven between the filled third series of tunnels, the tunnels of the fourth series being connected to the decline by the second passage.
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In a subsequent aspect of the invention, the fourth series of tunnels and the second passage are filled with support material. A fifth series of spaced tunnels of substantially equal widths extends parallel to one another in a third horizontally passage at a third level. The third direction also may be transverse to the first direction. The spacing between adjacent tunnels is substantially equal to or greater than the widths of adjacent tunnels.
In a subsequent aspect of the invention, the fifth series of tunnels is filled with support material. A sixth series of tunnels is located between the filled fifth series of tunnels, the tunnels of the sixth series being connected to the decline by the third passage.
In a subsequent aspect of the invention, the sixth series of tunnels and the third passage are filled with support material. A seventh series of spaced tunnels extends parallel to one another in a fourth horizontal direction and is connected to the decline by a fourth horizontal passage at a fourth level. The fourth direction is transverse to the third direction. The fourth direction generally would be transverse to the second direction. The spacing between adjacent tunnels is substantially equal to or greater than the widths of the adjacent tunnels.
go ~311~?6 g In a subsequent aspect of the invention, the seventh series of tunnels it filled with support material. An eighth series of tunnels is located between the filled seventh series of tunnels, the tunnels of the eighth series being connected to the decline by the fourth passage.
Relative lateral inclinations of the tunnels at descending levels may be selected so as to provide repeating, progressive directional sequences, reoccurring each three or four levels, so as to provide in effect, a vertically superimposed lattice work of laterally inclined beams.
The method of excavation of the present invention comprises excavating a decline and then driving a first series of spaced tunnels in a first direction at a first level of the decline. The first series of tunnels would then be filled with support material. A second series of tunnels would then be driven between the filled tunnels of the first series.
In selecting angles of lateral inclination of the tunnels at descending levels of the excavation care is taken that the overlying beam support structures, which in effect constitute the roof portions for the immediately underlying tunnels in area of excavation, extend generally transversely of the tunnels, so as to limit the unsupported span of the respective beam structures until such time as the respective I
tunnels are backfilled into potential load supporting relation with the superposed beams.
The tunnels of the second series would then normally be filled with support material and a third series of spaced tunnels may then be driven in a second direction from a second level of the decline, the second direction being laterally transverse to the first direction. The tunnels of the third series would then be filled with support material and a fourth series of tunnels then driven between the filled tunnels of the third series.
The tunnels of the fourth series may be filled with support material and a fifth and succeeding series of spaced tunnels then driven in a predetermined changed directions at respective deeper levels of the decline.
In carrying out the presently disclosed method of excavation a succeeding series of tunnels, excavated at a given level normally utilize a common connecting passage to access the decline, from which access passage the tunnels extend, often from both sides of the passage, by virtue of its location intermediately of the area encompassed by the respective level.
The present invention thus provides, in the excavation of a level, being one of a number of proposed descending levels .
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of excavation, the subject level extending laterally from adjacent a decline passage, being accessed therefrom by a connecting passage, wherein a first plurality of generally parallel, mutually spaced apart tunnels extend at a predetermined angle of lateral inclination from the connecting passage, the improvement comprising a plurality of separate, first monolithic beams within the tunnels, Mach being in load transfer relation with an underlying layer and having fill in load transfer, strata stabilizing relation deposited thereon, to substantially backfill the excavation above the beams.
There is further provided at that level a plurality of second tunnels each extending laterally contiguously between adjacent tunnels of the first plurality of tunnels, the second tunnels each having therein a monolithic second beam substantially contiguous with adjacent ones of the first plurality of monolithic beams.
The second tunnels have fill deposited on the beams to fill the excavation there above.
In the preferred embodiment the subject monolithic beams comprise a concrete layer extending widths and along substantially the length of the respective tunnel. The concrete of the beams may include reinforcement elements therein, depending upon the anticipated load requirements in the respective strata.
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In order to facilitate the construction of the beams and to ensure optimum utilization of them, a layer of substantially unconsolidated material such as sand is generally deposited in the base of the tunnels, over which an impermeable layer, such as a layer of plastic is laid, to form a bed for the respective beam, onto which it is poured. Furthermore, during tunnellin~ of the succeeding level there beneath, the sand layer protects the beam by permitting safe undercutting in relation thereto, so that generally the sand falls away and is removed.
While being influenced, dimensionally, by the nature of the material being excavated, in a fully mechanized operation the tunnels of the initial series, at any one level would be size limited, particularly laterally to a range of abut three to five metros, to satisfy equipment and operational requirements; in particular to reduce the requirement for structural bracing and reinforcement, while the subsequent loaded stress levels of the concrete beams placed in the tunnels also are limited. Tunnel heights are generally about three metros or greater, primarily to satisfy equipment and operational requirements.
In the preferred mode, the initial unconsolidated layer such as sand, typically about one half moire thick has an impervious plastic sheet laid there over, to serve as a diaphragm Jo "I
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both in the pouring of the concrete, to facilitate the curing thereof, and to assist in containment of the hydraulically placed back fill layers there above.
The preferred concrete beams generally comprise a layer of one to one and a half metros thick, typically of 3000 pounds per square inch concrete, poured onto the plastic and contained laterally by toe walls of the tunnel. Reinforcement for the concrete may be introduced, if structurally required.
Alternatively structural metal, such as steel, may be used. If metal plate of substantial area covering form is used, it may serve as the impervious layer.
Is is contemplated that the efficient utilization of the reinforcement concrete may be enhanced by suitably profiling the upper surface of the underlying sand layer, along the length of the respective tunnel, to thereby form to a desired configuration the undersurface of the beam so formed.
In the driving of the underlying tunnels in the succeeding level, as a for-instance, the succeeding beams encountered could provide sequential barrel-vau]ted roof portions. It is recognized that certain consequences could flow, in regard to back filling of such transverse, barrel-vaulted roof which might diminish the accrued advantage of such structural improvement.
These various aspect of the invention may be repeated in sequence to the lowest level of the excavation as desired.
The excavation and method of excavation of the present invention will be described with reference to a method of mining and a mine, a preferred embodiment of which is illustrated in the drawings, wherein:
Figure 1 is an exploded series of time sequential isometric views of three levels of an ore body, each of which have been partially subject to the excavation of the present invention;
Figure 2 is a plan view of the upper level shown in Figure 1, with a plan view of the underlying and subsequent middle level of Figure 1 being shown in dashed form;
Figure 3 is a plan view of the middle level of Figure 1, with a plan view of the underlying and subsequent lower level of Figure 1 being shown in dashed form;
Figure 4 is a plan view of the lower level of Figure l; and Figure 5 is a time lapsed sequential section taken along lines 5-5 in Figures 1, 2, 3 and 4 at respective times when the subject level which those Figures illustrate had been I, ~Z3~
driven, reinforced and backfilled, but prior to drilling of the succeeding, lower level.
Referring first to Figure 1, it represents three slabs or levels of a geological body, 10 exploded for ease of reference and shown at sequential time intervals. An upper slab, 12 lies above a middle slab, 14 which, in turn, lies above a lower slab, 16. Relative to the other slabs, the upper slab, 12 is shown at the earliest time interval. As the preferred embodiment will be described and illustrated with reference to mining operations and the mine illustrated, it will be assumed that the geological body, 10 is beneath the earths surface, which is not shown, and is, in part, an ore body. However, the present invention may be used in connection with any load bearing material such as rock, soil or sand.
Ore bodies are generally tabular and lie at a random angle to the surface. Access to the ore body may he made by a sloped decline tunnel from the surface at the edge of the ore body. The decline typically may be a conventional trackless passage. The decline typically enables removal of the excavated material from the excavation, in this case mined ore, and supply of fill material. In Figure 1, a portion of the decline, 18 is shown in each slab. However, the decline, 18 is continuous from the surface to the lowest level of the excavation. The decline is located in that portion of the slab where there is no ore to be mined.
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After at least a portion of the decline, 18 is excavated, a first access passage, 24 is provided, and a series of spaced tunnels, 20 is driven in a first direction, 22 at the first level, 12 of the decline, 18. The tunnels of the first series, 20, shown in plan view in Figure 2, are parallel to each other and driven in a horizontal plane. They are connected to the decline by the horizontal passage, 24. The tunnels of the first series, 20 are of substantially equal widths w and the spacing S between adjacent tunnels of the lo first series, 20 is substantially equal to or greater than the widths W of adjacent tunnels, 20.
The widths of the tunnel are determined by, among other factors, the material through which they are drilled.
Typically the widths of the tunnels are between three I and five (5) metros to satisfy equipment and operational requirements. By thus keeping the widths of the tunnels, 20 relatively narrow, the requirement for structural bracing and reinforcement is reduced and the concrete beams to be placed in the tunnels during subsequent filling operations are kept from being over stressed. Typically the heights H of the tunnels are about three (3) metros or greater to satisfy equipment and operational requirements. While the tunnels and the horizontal passages described and illustrated are typically horizontal, they may be sloped at an angle which can he negotiated by a tracked vehicle I
It is after this step of the method that the excavation is illustrated in -the upper slab, I of Figure 1 and in Figure 2. At this stage, the excavation comprises the decline, lo and a first series of spaced horizontal tunnels, 20 connected to the decline, 18 ho a first horizontal passage, 24.
The first series of tunnels, 20 are then filled with support material. This phase, represented in Figure 5 of the drawings, enables the void left by thy tunneling to be filled in order to structurally stabilize the ore body, 10. Although the tunnels of the first series, 20 are filled, the first horizontal passage, 24 is not filled at this stage.
The support material, shown in Figure 5 is a Tim elapse cross section of all three levels of Figure 1 showing the entire series of excavation, reinforcement and back fill for the illustrated three levels when respectively completed. It generally comprises a layer of previous unconsolidated material, 26, which subsequently generally falls into the succeeding, lower level during the driving thereof), a layer of impervious material, 28, a structural layer of load bearing material, 30 and a layer of bulk fill, 32. The previous material, 26 is typically a half (1~2) moire layer of sand plastic may be used as the impervious layer, 28. Preferably, the load bearing material is concrete. However structural metal such as steel may be used. If metal plate is used, it I
may serve as both the impervious end structural layers. A one (1) to one and a half (1 1i2~ moire layer of concrete is typical, although the exact thickness will be determined by the span adopted for the underlying tunnels. The widths of crossing tunnels in the levels above and below will determine whether or not reinforcement of the concrete is required. The bulk fill layer, I may be low strength cemented sand or uncemented sand. In the embodiment shown in the bottom level of Figure 5, the bulk fill, 32 lies above the concrete, 30, which lies above the plastic, 28, which, in turn, sits on the previous sand layer, 26. The various layers act as fill layers, while the structural concrete layer acts also as a beam to shed the load of the levels above. The initial presence of the unconsolidated layer, 26 enables drilling of tunnels in the layer beneath without any damage to the structural layer, which structural layer then forms the roof for the succeeding, underlying tunnels.
A second series of tunnels snot shown in the drawings is then driven in the spaces, 34 between the filled tunnels of the first series, 20. Because the tunnels of the first series, 20 are parallel and of equal widths and are illustrated as being equally spaced, the tunnels of the second series, 34 will be likewise. At this stave of the operation, the excavation comprises a decline, 18 and a first series of spaced tunnels, 20 connected to the decline, 18, the tunnels of the first I
lug --series, 20 being filled with support material, and a second series of tunnels, 34 between the filled tunnels of the first series, 20. It will be understood that size of the tunnels, 34 of the second series will equal the spacing between the tunnels, 20, and may well exceed the size of the tunnels, 20.
The tunnels of the second series t34) and optionally the first horizontal connecting passage, 24 are then filled with support material. The decline, 18 is then further extended to the next level, 14 of the excavation. A third lo series of spaced tunnels, 36 is then driven in a second laterally oriented direction, 38, the second direction, 38 being transverse to the first laterally oriented direction, 22. By driving the third series of tunnels, 36 in the second direction, 38, the third series of tunnels underlie and are traversed by the hems former by the reinforcement of the tunnels, 20 of the first level and tunnels ~34) of the second series above. The lateral orientation Al relation between the tunnels, 36 of the third series and those of the first level, 12 there above may be seen from Figure 2, where the dash lines represent the second level, 14 after drilling of the third series of the tunnels, 36.
The horizontal tunnels of the third series, 36 are connected to the decline, 18 by the second horizontal passage, 40. The tunnels of the third series, 36 are of substantially ~.~
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equal widths W and the spacing S between adjacent tunnels of the third series, 36 is shown to be substantially equal to, but could well be greater than the widths of adjacent tunnels, 36.
At this stage of the operation, illustrated by the middle slab, 14 of Figure 1 and by Figure 3, the excavation comprises a decline, 18 and a first series of spaced tunnels, 20 in a first direction, 22, the tunnels, 20 being connected to the decline, 18 at a first level, 12 and filled with support material. A second series of tunnels, 34 is between the tunnels of the first series, 20, the tunnels of the second series, 36 being filled ilk support material. A third series of spaced tunnels, 36 is in a second direction, 38 and is connected to the decline, 18 by a second horizontal passage, 40 at a second level, 14. The second direction, 38 is transverse to the first direction, 22.
The tunnels of the third series, 36 are then filled with support material and a fourth series of tunnels, 42 is then driven between the filled tunnels of the third series, 36. The relation between the tunnels of the fourth series, 42 to those of the third series, 36 is analogous to the relation between the tunnels of the second series, 34 and those of the first series, 20. In other words, the tunnels of the fourth series, 42 are parallel and of substantially equal widths W and the spacing S between adjacent tunnels of the fourth series, 42 lo 3 by is substantially equal to or greater than to the widths of the adjacent tunnels, 42.
At this stage of the operation, which is not illustrated, the excavation comprises a decline, 18 and a first series of spaced tunnels, 20 in a first direction, 22, the tunnels of the first series, 20 being connected to the decline, 18 at a first level, 12 by a first horizontal passage, 24 and filled with support material. A second series of tunnels, 34 is between the tunnels of the first series, 20, the tunnels of the second series, 34 and the first horizontal passage, 24 being filled with support material. A third series of spaced tunnels, 36 is in a second direction, 38 and connected to the decline, 18 at a second level, 14 by a second horizontal passage, 40, the second direction, 38 being transverse to the first direction, 22 and the tunnels of the third series, 36 being filled with support material. A fourth series of tunnels, 42 is between the tunnels of the third series, 36.
The tunnels of the fourth series, 42 and the second horizontal passage, 40 are then filled with support material.
A fifth series of spaced tunnels, 44 is driven in a third direction, 46 at a third level, 16 of the decline, 18 by a third horizontal passage, 48. The third direction, 46 is transverse to the first direction, 22.
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An alternate fifth series of spaced tunnels, 50 may be driven in an alternate third direction, 52 at the third level, 16 of the decline, 18, the tunnels of the alternate fifth series, 50 being connected to the decline by the third horizontal passage, 43. The alternate third direction, 52 is transverse to both the first, 22 and second, 38 directions.
The relative transverse directions of adjoining levels creates a cross-wise lattice-work of beams as level after level of the ore body, 10 is excavated and subsequently filled.
As was the case for the tunnels, 20 of the first series and tunnels, 36 of the third series, the tunnels, 44 of the fifth series are parallel and of substantially equal widths W; the spacing S between adjacent tunnels, 44 of the fifth series is substantially equal to or greater than the widths w of the tunnels, 44.
At this stage of the operation, which is illustrated by the lower level, slab 16 in Figure 1 and by Figure 4, the excavation comprises a decline, 18 and a first series of spaced tunnels, 20 in a first direction, 22, the tunnels, 20 being Jo connected to the decline, 18 at a first level, 12 by a first horizontal passage, 24 and filled with support maternal. A
second series of tunnels, 34 is driven between the tunnels of the first series, 20, the tunnels of the second series, 34 and optionally the first horizontal passage, 24 being filled with ~Z3~
support material. A third series of spaced tunnels, 36 is in a second direction, 38 and connected to the decline, 18 by a second horizontal passage, 40 at a second level, 14. The second direction, 38 is transverse to the first direction, 22 and the tunnels of the third series, 36 are filled with support material. A fourth series of tunnels, 42 is between the tunnels of the third series, 36, thy tunnels of the fourth series, 42 and optionally the second horizontal passage, 40 being filled with support material. A fifth series of tunnels, 44 or 50 is in a third direction, 46 or 52, respectively and is connected to the decline, 18 by a third horizontal passage, 48 at a third level, 16, the third direction, 46 or 52 being transverse to the second direction and, in some cases, 52 transverse to the first direction, 22.
The tunnels of the fifth series, 44, 50 are then filled with support material. A sixth series of tunnels, 54 is then driven between the filled tunnels of the fifth series, 44, 50. The relation between the tunnels of the sixth series, 54 to whose of the third series, 44, 50 is analogous to those of the first, 20 and second, 34 and to those of the third, 36 and fourth, 42 series. The tunnels of the sixth series, 54 are parallel and of substantially equal widths W, and the spacing S
between adjacent tunnels of the sixth series, 54 is substantially equal to or greater than the widths W of the tunnels.
The tunnels of the sixth series, 54 and optionally the third horizontal passage, 48 are then filled with support material. A seventh series of spaced tunnels, not shown, may be driven in a fourth direction at a fourth level of the decline, 18, the fourth direction being transverse to the third direction, 46 (or 2). The fourth direction may also be transverse to the second direction, 38. The tunnels of the seventh series may be identically laterally oriented to those of the first series of tunnels, 20, by which the lateral orientation pattern of tunnels could repeat every three levels.
The tunnels of the seventh series would then be filled with support material. An eighth series of horizontal tunnels may then be driven between the filled tunnels of the seventh series. The tunnels of the eighth series may correspond in lateral orientation, size and spacing to the tunnels of the second series, 34 in that they are parallel and of substantially equal widths W. The spacing S between adjacent tunnels of the eighth series is substantially equal or greater than the widths of adjacent tunnels. The tunnels of the eighth series are connected to the decline, 18 by a fourth horizontal passage.
The tunnels of the eighth series and the associated fourth horizontal passage are then filled and the next level downward is excavated, in each case the tunnels of each level being transverse to those of the level above.
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The various steps in the method of the invention may be repeated in sequence or otherwise to the lowest level of the excavation.
If it is desirable to retain an open room at any level of the excavation, this can be done by omitting the filling step in respect of selected tunnels. If the room is desired to be of substantial width, the structural reinforcement layer in the tunnels of the level above might be additionally suitably strengthened.
The completed excavation will appear to be similar in make-up for each application of the method, but the number of tunnels being simultaneously driven can vary according to the rock competency. It should be understood that each series of tunnels may be subdivided into sub-series with intermediate filling or that more than one series of tunnels may be drilled at any level if ground conditions permit such an approach.
While the conventional system of hydraulic or pneumatic drilling, blasting and load-haul-dump mucking may be used to excavate, the method of the present invention may be used with tunnel boring machines and similar rock cutting and boring machines. Fill may be placed by a pneumatic blower or by wheeled transportation. Survey control of the operation should be constant and may be effected by the use of a laser ~23~
- 2Ç -system. Ventilation of the excavation may be effected by way of the decline through the horizontal passage at the level hying excavated.
The method of excavation and the excavation of the present invention is particularly suited to the mining of wide ore bodies. It is the width of wide ore bodies that leads to problems in that the excavation becomes less stable as the width increases. The method and form of the excavation disclosed and claimed sheds the load from the roof of any tunnel to the supporting strata below. By using low strength bulk fill between the high strength concrete beams, the fill can absorb pressure instead of transmitting it. By contrast, in the traditional undercut-and-fill system, the fill used is not strong enough to be stable over wide spans. By using a cross-wise lattice, the method and excavation of the present invention reduces the exposed span to a width controlled by engineering decision rather than by the vagaries of the ore body. The strength of the excavation is increased while the risk imposed by the general lack of homogeneity in rock masses is reduced.
While a specific embodiment of the invention has been disclosed and illustrated herein, it is to be understood that variations and modifications are possible without departing ~33~ I
from the spirit or essence of this invention. The method of excavation and the excavation may be applicable to operations other than mining, although the disclosure and drawings are directed to an embodiment in the mining field.
7290b/1-29
Claims (40)
PROPERTY OF PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In an excavation of a level, being one of the number of proposed levels of excavation said level extending adjacent a decline passage, being connected to the decline passage by an interconnecting passage, wherein a first plurality of generally parallel, mutually spaced apart tunnels extend at a predetermined angle of lateral inclination in the first level, the improvement comprising a plurality of separate, first monolithic beams deposited upon a layer of pervious, substantially unconsolidated material within the tunnels, each being in load transfer relation with an underlying layer and having fill in load transfer strata stabilizing relation deposited thereon, to substantially back fill the excavation thereabove.
2. The excavation as set forth in claim 1, including a plurality of second tunnels at said first level, each extending laterally between adjacent tunnels of said first plurality of tunnels and having therein a second monolithic beam substantially contiguous along the length thereof with adjacent ones of said first monolithic beams.
3. The excavation as set forth in claim 2, wherein said plurality of second tunnels have fill deposited on said beams to fill the excavation thereabove.
4. The excavation as set forth in claim 1, a monolithic beam of said plurality of beams comprising a concrete layer extending substantially the full width of a respective said tunnel.
5. The excavation as set forth in claim 4, said concrete layer including reinforcement elements therein.
6. The excavation as set forth in claim 2, said first plurality and said second plurality of tunnels each containing a said monolithic beam extending wall to wall therein, said beams being in substantially laterally abutting relation to comprise a laterally laminated, substantially continuous support layer.
7. The excavation as set forth in claim 2, having respective said levels tunneled laterally from a said decline passage, the tunnels of each layer being laterally inclined at a substantial angle from the tunnels of the superposed layer.
8. The excavation as set forth in claim 4, said concrete layer being deposited upon a substantially impervious layer.
9. The excavation as set forth in claim 8, said impervious layer being deposited on a layer of unconsolidated pervious support material.
10. The excavation as set forth in claim 9, each said tunnel being filled with bulk fill material in superposed filling relation above said concrete layer.
11. The excavation as set forth in claim 10, said superposed monolithic beams of each said level forming a vertical lattice of beams having bulk fill material in load transfer relation therebetween.
12. The excavation as set forth in claim 2, wherein the lateral spacing between said first plurality of tunnels is substantially equal to the respective width of said tunnels whereby said monolithic beams each comprises a layer of high strength material lying in substantially contiguous parallel strips of substantially equal widths, over the area excavated.
13. The excavation as set forth in claim 2, wherein the lateral spacing between said first plurality of tunnels exceeds the width of the tunnels, whereby said second plurality of tunnels each exceeds in width the width of the first plurality of tunnels.
14. The excavation as set forth in claim 12 or claim 13, wherein said high strength material layer comprises a layer of concrete.
15. The excavation as set forth in claim 12 or claim 13, wherein said high strength material layer comprises a layer of reinforced concrete.
16. The excavation as set forth in claim 7, having additional pluralities of tunnels at said second and at lower levels, including a substantial layer of high strength material deposited at least in each tunnel at levels above the bottom level of the excavation; the tunnels of succeeding layers being laterally inclined from the tunnels of the overlying level, to present a lattice of mutually laterally inclined beams in spaced apart layers, having load transfer, bulk fill layers interposed therebetween.
17. The excavation as set forth in claim 1, claim 12 or claim 13, said tunnels having widths in the range substantially between ten and seventeen feet, and generally being at least ten feet in height.
18. The excavation as set forth in claim 12 or claim 13, said high strength material layer comprising a layer of concrete having thickness substantially in the range of three to five feet.
19. The method of underground excavation from a decline extending below ground level, comprising the steps of:
excavating a connecting passage at a first level, connecting with the decline;
excavating a first plurality of substantially mutually parallel tunnels transversely of the level from the connecting passage;
forming first monolithic load supporting beam members in a plurality of the tunnels, extending substantially the full width thereof, and excavating a second plurality of tunnels parallel with and alternating with the first plurality of tunnels, in substantially contiguous relation therewith.
excavating a connecting passage at a first level, connecting with the decline;
excavating a first plurality of substantially mutually parallel tunnels transversely of the level from the connecting passage;
forming first monolithic load supporting beam members in a plurality of the tunnels, extending substantially the full width thereof, and excavating a second plurality of tunnels parallel with and alternating with the first plurality of tunnels, in substantially contiguous relation therewith.
20. The method as set forth in claim 19, including the step of filling said first plurality of kennels, above said beam members with bulk fill material.
21. The method as set forth in claim 19, including the step of forming a monolithic load supporting beam member in each of said second plurality of tunnels in substantially contiguous relation along the length thereof with said first beam members.
22. The method as set forth in claim 19, including providing an unconsolidated support layer below said beam members.
23. The method as set forth in claim 22, including positioning an impervious layer over said unconsolidated support layer prior to the forming of said beam members.
24. The method as set forth in claim 19, wherein said first plurality of tunnels are substantially transversely equi-spaced by a distance at least equal to the width of said first series of tunnels.
25. The method as set forth in claim 24, wherein said distance is greater than the width of said first tunnels, and equal to the width of said second tunnels.
26. The method as set forth in claim 21, further including the steps of excavating at a second level below said first level a third series of substantially mutually parallel tunnels, being laterally inclined from said first and second series of tunnels.
27. The method as set forth in claim 26, including forming a monolithic beam member in each of said third series of tunnels.
28. The method as set forth in claim 27, including filling said third series of tunnels above said beam member with bulk fill material in load transfer relation therewith.
29. The method as set forth in claim 28, including excavating at said second level a fourth series of tunnels parallel with said third series, and forming therein supporting beam members in substantially contiguous relation with said beam members in said third series of tunnels.
30. The method as set forth in claim 29, including excavating pluralities of tunnels at succeeding deeper levels beneath said first and said second levels and providing in a plurality of said tunnels supporting beam members having bulk fill material thereabove in load transfer relation therewith to substantially preclude subsidence within said excavation.
31. The method as set forth in claim 19, claim 24 or claim 25, wherein said first plurality of tunnels have widths substantially in the range from ten to seventeen feet.
32. The method as set forth in claim 19, claim 24 or claim 25 wherein said tunnels when excavated have a height of about ten feet or more.
33. The method as set forth in claim 19, claim 24 or claim 25, wherein said beam members are of concrete, having a depth in the range of about three to five feet.
34. The method as set forth in claim 26, wherein said third series of tunnels is inclined laterally at an angle of less than 90° from said first and second series of tunnels.
35. The method as set forth in claim 26, wherein said tunnels at said second level are connected by a connecting passage to said decline.
36. The method as set forth in claim 30, said tunnels at said levels being connected at each level by a connecting passage with a said decline, said connecting passages being arranged in substantially non-overlying relation with connecting passages lying there below.
37. The method as set forth in claim 30, said tunnels at each succeeding level being laterally inclined from the tunnels in the above proceeding level at an angle of less than 90°.
38. the method as set forth in claim 37, wherein said tunnels are laterally angled from one level to the next to provide repeating sequences of angular orientation of not less than three levels per sequence.
39. The method as set forth in claim 30, including filling selected ones of said connecting passages at selected levels of the excavation.
40. The method as set forth in claim 19, including profiling the under surface of said beam members in transverse relation thereto, to enhance the local load bearing efficiency thereof.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000469428A CA1231106A (en) | 1984-12-05 | 1984-12-05 | Excavation and method of excavation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000469428A CA1231106A (en) | 1984-12-05 | 1984-12-05 | Excavation and method of excavation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1231106A true CA1231106A (en) | 1988-01-05 |
Family
ID=4129315
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000469428A Expired CA1231106A (en) | 1984-12-05 | 1984-12-05 | Excavation and method of excavation |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1231106A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113431586A (en) * | 2021-07-07 | 2021-09-24 | 中铁一局集团厦门建设工程有限公司 | Anhydrous construction method for underground excavation region of subway |
-
1984
- 1984-12-05 CA CA000469428A patent/CA1231106A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113431586A (en) * | 2021-07-07 | 2021-09-24 | 中铁一局集团厦门建设工程有限公司 | Anhydrous construction method for underground excavation region of subway |
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