CA2243016A1 - Concrete block mining method - Google Patents
Concrete block mining method Download PDFInfo
- Publication number
- CA2243016A1 CA2243016A1 CA 2243016 CA2243016A CA2243016A1 CA 2243016 A1 CA2243016 A1 CA 2243016A1 CA 2243016 CA2243016 CA 2243016 CA 2243016 A CA2243016 A CA 2243016A CA 2243016 A1 CA2243016 A1 CA 2243016A1
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- CA
- Canada
- Prior art keywords
- gallery
- concrete
- subsurface
- collapsing
- horizontal
- 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.)
- Abandoned
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C41/00—Methods of underground or surface mining; Layouts therefor
- E21C41/16—Methods of underground mining; Layouts therefor
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
- E21D9/001—Improving soil or rock, e.g. by freezing; Injections
Abstract
A method of constructing a concrete-lined horizontal gallery in an unstable subsurface, and a mining method which uses such method. The former comprises freezing a zone of unstable subsurface extending in a selected horizontal direction from an established gallery or shaft, then excavating a preliminary chamber having a non-collapsing frozen periphery from within a frozen perimeter of the zone, then completely filling said preliminary chamber with settable concrete, and, after the concrete has set, excavating a final chamber having a non-collapsing concrete periphery and gallery dimensions from within an outer perimeter of the concrete, thereby forming a non-collapsing concrete-lined extension of the established gallery. The method is especially useful in mining an ore body surrounded by unstable subsurface, such as clay.
Description
CONCRETE BLOCK MINING METHOD
The present invention relates to a method of mining a deposit in unstable subsurface conditions, such as caused by clay or an aquifer.
An ore deposit located in an unstable subsurface may pose a serious challenge to efforts to mine the deposit, particularly where the unstable subsurface surrounds the deposit. For example, the surrounding unstable conditions typically prevent or hinder drifting of stable working galleries above, to a side, or below the deposit. If the deposit is hazardous, such as in the case of a deposit of high grade uranium, there is the additional risk of water borne contamination coming from the ore source through unstable subsurface and penetrating any development drift in the vicinity of the ore body.
Problems from unstable subsurface encountered in the context of applying various known mining methods have prompted the development of specific solutions. For example, U.S.
Patent No. 4,431,341, issued to Nilberg, discloses a method of constructing a concrete-lined, subsurface chamber along a bore hole. The chamber may be used for conducting mining operations such as horizontal drilling. In this method a concrete-lined bell-shaped chamber is made by steps which include excavating concrete from within side-walls of an initially poured and hardened bell-shaped concrete mass. Thus, the remaining concrete acts as a support liner for the excavated space. The method is stated to be particularly useful in unstable subsurfaces such as tar sands and oil sands. We note that the method does not involve any transient stabilizing of the subsurface by the use of freezing. It may be that compressed air would be used to keep the excavation from collapsing during the construction phase compression chambers created would prevent the flooding of the excavation while it was being mined and before the concrete lining was completed. The method is also for use in vertical bore hole applications and is neither taught nor appears to be workable in connection with a horizontal excavation of a mine gallery through unstable subsurface.
United States Patent No. 4,516,878 issued to Rebhan describes horizontal tunnel building, rather than a mining method, using the concept of freezing soil. In this method, a soil freezing work pipe is inserted into a hole bored along the axis of a planned tunnel and the soil is cooled until a frozen soil mass is formed around the work pipe. When the frozen mass has a diametre greater than that of the planned tunnel, frozen soil is excavated while leaving a frozen soil lining. Such lining is then immediately supported by a primary or permanent support lining. The primary support lining may be blown or injected concrete, and the permanent lining may be extruded or reinforced concrete. The establishment of the primary and permanent linings is conventional but unsatisfactory in application to mining unstable subsurface where massive support is required for an excavated area.
Canadian Patent No. 210,592 issued to Stuckey discloses a method of mining shafts, stopes or drives which consists of drilling a hole to intersect water bearing or conveying crevices, closing the mouth of the hole, forcing cement or other solidifying material into the hole whereby the bore and surrounding crevices are filled with solid material so as to prevent the flow of water in the crevices, and subsequently removing the rock or matrix in the hole by ordinary mining operations. This method is principally used to gout or fill cracks in rock and not to stabilize poor or unstable ground.
There is no indication how this method may work in particularly unstable subsurface conditions where the initial bore hole cannot remain intact until the subsequent steps are performed.
It is not possible to inject cement into massive clays or similar unstable ground as any cracks that may develop in clays are usually filled by that material because of its elastic properties. This method therefore also appears to be entirely unsuitable to producing a horizontal working gallery in poor subsurface conditions.
Finally, Canadian Patent No. 21, 176, which issued in 1885, discloses a method of sinking shafts through unstable subsurfaces, which method includes freezing a portion of the subsurface. Freeze pipes are used to freeze the relevant area whereupon excavation of the resulting frozen block may be performed. The freezing is maintained until the excavated shaft is lined entirely and finished in masonry or other permanent material. This patent relates to vertical shaft construction and does not teach any application to horizontal gallery excavation through surrounding unstable subsurface.
The above sampling of known methods fails to reveal any method which would be useful in excavating horizontal mine galleries through surrounding unstable subsurface in a manner so as to provide a secure, potentially permanent gallery, in particular a working gallery for an ore deposit.
SUMMARY OF THE INVENTION
The invention therefore provides, in one aspect, a method of constructing a concrete-lined horizontal gallery in an unstable subsurface. Firstly, from an established gallery or shaft, a zone of unstable subsurface is frozen extending in a selected horizontal direction. The zone has preselected dimensions for eventually accommodating the horizontal gallery in accordance with the following described method steps. Next, a preliminary chamber is excavated, so as to have a non-collapsing frozen periphery, from within a frozen perimeter of the zone. The preliminary chamber has dimensions selected to correspond to an outer perimeter of a non-collapsing concrete lining of the concrete-lined horizontal gallery to be subsequently formed in the preliminary chamber. The preliminary chamber is then completely filled with settable concrete. After the concrete has set, a final chamber is excavated from within an outer perimeter of the concrete so as to have a non-collapsing concrete periphery as well as gallery dimensions, thereby forming a non-collapsing concrete-lined horizontal gallery. It may be preferred, before mining the final chamber, that a series of preliminary chambers are mined and filled with suitable concrete in order to establish the massive concrete block from within which the final chamber is established.
In another aspect of the invention, there is provided a method of mining a deposit located in unstable subsurface, which method comprises, firstly, sinking a shaft in substantially stable subsurface at least to a depth from which a horizontal gallery may be extended partly through stable subsurface towards a preselected location in unstable subsurface for constructing a working gallery for the deposit.
Preferably, there are two such horizontal galleries, one for extending above and the other below the deposit. Secondly, the method comprises extending a horizontal gallery from the shaft towards the preselected location through substantially stable subsurface until intervening unstable subsurface is encountered. Next, a zone of unstable subsurface is frozen extending, from where the intervening unstable subsurface is encountered, in a horizontal direction towards said preselected location, the zone having preselected dimensions for accommodating an extension of the horizontal gallery in accordance with construction steps described subsequently. A
preliminary chamber is then excavated which has a non-collapsing frozen periphery from within a frozen perimeter of the zone, the preliminary chamber having dimensions corresponding to an outer perimeter of a non-collapsing concrete lining of a gallery selected to be formed in the preliminary chamber. The preliminary chamber is then completely filled with settable concrete, the concrete is allowed to set, and a final chamber having a non-collapsing concrete periphery and gallery dimensions is excavated from within an outer perimeter of the concrete, thereby forming a non-collapsing concrete-lined gallery. The steps of freezing a zone through to excavation of a concrete lined gallery may be repeated sequentially to advance construction of the horizontal gallery until a working gallery is provided at the preselected location. Once the working gallery has been formed, mining of the deposit occurs from the working gallery.
It is an advantage of the present methods of the invention that there would be a substantial contribution to the sealing of all fissures through which water might percolate, and thereby prevent deteriorating ground conditions from being established if any conventional mining might be established.
In addition, such methods would also serve as a shield from certain kinds of radiation that emanate from a high grade uranium deposit, and would serve as a base from which other protective methods for other forms of radiation could be controlled.
BRIEF DESCRIPTION OF THE DRAWINGS
In drawings representing a preferred embodiment of the present invention, Figure 1 illustrates a vertical section through subsurface in which the early stages of freezing and initial subsurface excavation according to the present method have been performed;
and Figure 2 illustrates a vertical section through subsurface in which the later stages of concrete filling and excavation of the concrete according to the present method have been performed.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention relates to a method of mining a deposit in unstable subsurface conditions, such as caused by clay or an aquifer.
An ore deposit located in an unstable subsurface may pose a serious challenge to efforts to mine the deposit, particularly where the unstable subsurface surrounds the deposit. For example, the surrounding unstable conditions typically prevent or hinder drifting of stable working galleries above, to a side, or below the deposit. If the deposit is hazardous, such as in the case of a deposit of high grade uranium, there is the additional risk of water borne contamination coming from the ore source through unstable subsurface and penetrating any development drift in the vicinity of the ore body.
Problems from unstable subsurface encountered in the context of applying various known mining methods have prompted the development of specific solutions. For example, U.S.
Patent No. 4,431,341, issued to Nilberg, discloses a method of constructing a concrete-lined, subsurface chamber along a bore hole. The chamber may be used for conducting mining operations such as horizontal drilling. In this method a concrete-lined bell-shaped chamber is made by steps which include excavating concrete from within side-walls of an initially poured and hardened bell-shaped concrete mass. Thus, the remaining concrete acts as a support liner for the excavated space. The method is stated to be particularly useful in unstable subsurfaces such as tar sands and oil sands. We note that the method does not involve any transient stabilizing of the subsurface by the use of freezing. It may be that compressed air would be used to keep the excavation from collapsing during the construction phase compression chambers created would prevent the flooding of the excavation while it was being mined and before the concrete lining was completed. The method is also for use in vertical bore hole applications and is neither taught nor appears to be workable in connection with a horizontal excavation of a mine gallery through unstable subsurface.
United States Patent No. 4,516,878 issued to Rebhan describes horizontal tunnel building, rather than a mining method, using the concept of freezing soil. In this method, a soil freezing work pipe is inserted into a hole bored along the axis of a planned tunnel and the soil is cooled until a frozen soil mass is formed around the work pipe. When the frozen mass has a diametre greater than that of the planned tunnel, frozen soil is excavated while leaving a frozen soil lining. Such lining is then immediately supported by a primary or permanent support lining. The primary support lining may be blown or injected concrete, and the permanent lining may be extruded or reinforced concrete. The establishment of the primary and permanent linings is conventional but unsatisfactory in application to mining unstable subsurface where massive support is required for an excavated area.
Canadian Patent No. 210,592 issued to Stuckey discloses a method of mining shafts, stopes or drives which consists of drilling a hole to intersect water bearing or conveying crevices, closing the mouth of the hole, forcing cement or other solidifying material into the hole whereby the bore and surrounding crevices are filled with solid material so as to prevent the flow of water in the crevices, and subsequently removing the rock or matrix in the hole by ordinary mining operations. This method is principally used to gout or fill cracks in rock and not to stabilize poor or unstable ground.
There is no indication how this method may work in particularly unstable subsurface conditions where the initial bore hole cannot remain intact until the subsequent steps are performed.
It is not possible to inject cement into massive clays or similar unstable ground as any cracks that may develop in clays are usually filled by that material because of its elastic properties. This method therefore also appears to be entirely unsuitable to producing a horizontal working gallery in poor subsurface conditions.
Finally, Canadian Patent No. 21, 176, which issued in 1885, discloses a method of sinking shafts through unstable subsurfaces, which method includes freezing a portion of the subsurface. Freeze pipes are used to freeze the relevant area whereupon excavation of the resulting frozen block may be performed. The freezing is maintained until the excavated shaft is lined entirely and finished in masonry or other permanent material. This patent relates to vertical shaft construction and does not teach any application to horizontal gallery excavation through surrounding unstable subsurface.
The above sampling of known methods fails to reveal any method which would be useful in excavating horizontal mine galleries through surrounding unstable subsurface in a manner so as to provide a secure, potentially permanent gallery, in particular a working gallery for an ore deposit.
SUMMARY OF THE INVENTION
The invention therefore provides, in one aspect, a method of constructing a concrete-lined horizontal gallery in an unstable subsurface. Firstly, from an established gallery or shaft, a zone of unstable subsurface is frozen extending in a selected horizontal direction. The zone has preselected dimensions for eventually accommodating the horizontal gallery in accordance with the following described method steps. Next, a preliminary chamber is excavated, so as to have a non-collapsing frozen periphery, from within a frozen perimeter of the zone. The preliminary chamber has dimensions selected to correspond to an outer perimeter of a non-collapsing concrete lining of the concrete-lined horizontal gallery to be subsequently formed in the preliminary chamber. The preliminary chamber is then completely filled with settable concrete. After the concrete has set, a final chamber is excavated from within an outer perimeter of the concrete so as to have a non-collapsing concrete periphery as well as gallery dimensions, thereby forming a non-collapsing concrete-lined horizontal gallery. It may be preferred, before mining the final chamber, that a series of preliminary chambers are mined and filled with suitable concrete in order to establish the massive concrete block from within which the final chamber is established.
In another aspect of the invention, there is provided a method of mining a deposit located in unstable subsurface, which method comprises, firstly, sinking a shaft in substantially stable subsurface at least to a depth from which a horizontal gallery may be extended partly through stable subsurface towards a preselected location in unstable subsurface for constructing a working gallery for the deposit.
Preferably, there are two such horizontal galleries, one for extending above and the other below the deposit. Secondly, the method comprises extending a horizontal gallery from the shaft towards the preselected location through substantially stable subsurface until intervening unstable subsurface is encountered. Next, a zone of unstable subsurface is frozen extending, from where the intervening unstable subsurface is encountered, in a horizontal direction towards said preselected location, the zone having preselected dimensions for accommodating an extension of the horizontal gallery in accordance with construction steps described subsequently. A
preliminary chamber is then excavated which has a non-collapsing frozen periphery from within a frozen perimeter of the zone, the preliminary chamber having dimensions corresponding to an outer perimeter of a non-collapsing concrete lining of a gallery selected to be formed in the preliminary chamber. The preliminary chamber is then completely filled with settable concrete, the concrete is allowed to set, and a final chamber having a non-collapsing concrete periphery and gallery dimensions is excavated from within an outer perimeter of the concrete, thereby forming a non-collapsing concrete-lined gallery. The steps of freezing a zone through to excavation of a concrete lined gallery may be repeated sequentially to advance construction of the horizontal gallery until a working gallery is provided at the preselected location. Once the working gallery has been formed, mining of the deposit occurs from the working gallery.
It is an advantage of the present methods of the invention that there would be a substantial contribution to the sealing of all fissures through which water might percolate, and thereby prevent deteriorating ground conditions from being established if any conventional mining might be established.
In addition, such methods would also serve as a shield from certain kinds of radiation that emanate from a high grade uranium deposit, and would serve as a base from which other protective methods for other forms of radiation could be controlled.
BRIEF DESCRIPTION OF THE DRAWINGS
In drawings representing a preferred embodiment of the present invention, Figure 1 illustrates a vertical section through subsurface in which the early stages of freezing and initial subsurface excavation according to the present method have been performed;
and Figure 2 illustrates a vertical section through subsurface in which the later stages of concrete filling and excavation of the concrete according to the present method have been performed.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present method uses the principle of freezing to support unstable ground while an excavation is being established. Following this, a permanent, massive support system is installed and then the temporary control, the freezing, is turned off once the permanent support is in place.
The present method is for use in gaining access to any part of an ore body which is not normally accessible using conventional horizontal mining methods. It is particularly applicable in some of the high grade uranium deposits in Northern Saskatchewan where the ore is surrounded by a halo of weak clay material which, once mined, does not have the intrinsic strength to stay open under normal conditions and allow permanent access for the removal of the ore. For the purposes of the Figures, access to a position above the ore body is described but this can apply to below or to any position where access is required.
The present method uses the freezing technique to gain access to the desired stoping position and establish a permanent access. Figure 1 shows an ore body and an access drift "A" at some distance above the ore body. Normally, the access drift cannot be mined beyond "A" to a position above the ore body due to instability of the surrounding subsurface, e.g.
clay. Preferably, a series of horizontally extending freeze-holes "B" are drilled around the position or access that is ideal for stoping the ore body, and a frozen ring is thus created in the clay. Once the unstable area is protected, i.e.
rendered stable by the freezing, an excavation "C" is established. Note that a temporary support perimeter of frozen clay is left around the excavation. The entire excavation "C" is then backfilled with competent concrete.
Once the concrete has set, a smaller excavation "D" (referring now to Figure 2) is made within the concrete to form an upper chamber for removal of the ore using, for example, raise bore stoping methods. It may be necessary to undertake a similar procedure to establish an access below the ore body by carrying out the same procedure at point "E". The thickness of the concrete around "D" will have to be designed to withstand the pressure that the clay or an aquifer exerts on the excavation.
Geoscientific calculations preferably are used the determine the desired thickness. This final excavation preferably should be done by using a Roadheading machine to establish "D" so that there is no weakening of the protective concrete such as may occur by using drill and blast methods.
The principal access established from "A" over the top of the ore body within a protective concrete shell provides the basic primary access for stoping. Preparation for stoping could proceed as follows: any preparation work for the stoping freeze hole drilling could be established. Raise boring could then be undertaken of frozen block below. The concrete block could be advanced laterally in both directions from within the block by drilling freeze holes, excavation of the original clay material, installing concrete and then excavating a mining chamber. The second chamber would be a continuation and joined to the initial concrete block excavation. As the chamber gets bigger, it will have to be supported internally to prevent collapse. Progressively the entire ore body can be accessed using lateral extension of the Raise Boring chamber, and mined.
Should cribbing be used as a support, then the excavation can effectively be kept open for the life of the mine.
The present method is innovative in that freezing is used to establish an access to the ore body and a concrete block is used to provide a competent shell from within which a permanent access for stoping is available. The freezing that is applied to gain access initially can be shut off once the concrete block has been established. The excavation within the concrete block can be maintained indefinitely using timber cribs and does not require backfilling as stoping advances and excavation within the prepared block extends in outward directions. The method will afford a minimum disruption to the surrounding clay area and, assuming the concrete block is adequately designed and supported, could be kept open indefinitely.
_g_
The present method is for use in gaining access to any part of an ore body which is not normally accessible using conventional horizontal mining methods. It is particularly applicable in some of the high grade uranium deposits in Northern Saskatchewan where the ore is surrounded by a halo of weak clay material which, once mined, does not have the intrinsic strength to stay open under normal conditions and allow permanent access for the removal of the ore. For the purposes of the Figures, access to a position above the ore body is described but this can apply to below or to any position where access is required.
The present method uses the freezing technique to gain access to the desired stoping position and establish a permanent access. Figure 1 shows an ore body and an access drift "A" at some distance above the ore body. Normally, the access drift cannot be mined beyond "A" to a position above the ore body due to instability of the surrounding subsurface, e.g.
clay. Preferably, a series of horizontally extending freeze-holes "B" are drilled around the position or access that is ideal for stoping the ore body, and a frozen ring is thus created in the clay. Once the unstable area is protected, i.e.
rendered stable by the freezing, an excavation "C" is established. Note that a temporary support perimeter of frozen clay is left around the excavation. The entire excavation "C" is then backfilled with competent concrete.
Once the concrete has set, a smaller excavation "D" (referring now to Figure 2) is made within the concrete to form an upper chamber for removal of the ore using, for example, raise bore stoping methods. It may be necessary to undertake a similar procedure to establish an access below the ore body by carrying out the same procedure at point "E". The thickness of the concrete around "D" will have to be designed to withstand the pressure that the clay or an aquifer exerts on the excavation.
Geoscientific calculations preferably are used the determine the desired thickness. This final excavation preferably should be done by using a Roadheading machine to establish "D" so that there is no weakening of the protective concrete such as may occur by using drill and blast methods.
The principal access established from "A" over the top of the ore body within a protective concrete shell provides the basic primary access for stoping. Preparation for stoping could proceed as follows: any preparation work for the stoping freeze hole drilling could be established. Raise boring could then be undertaken of frozen block below. The concrete block could be advanced laterally in both directions from within the block by drilling freeze holes, excavation of the original clay material, installing concrete and then excavating a mining chamber. The second chamber would be a continuation and joined to the initial concrete block excavation. As the chamber gets bigger, it will have to be supported internally to prevent collapse. Progressively the entire ore body can be accessed using lateral extension of the Raise Boring chamber, and mined.
Should cribbing be used as a support, then the excavation can effectively be kept open for the life of the mine.
The present method is innovative in that freezing is used to establish an access to the ore body and a concrete block is used to provide a competent shell from within which a permanent access for stoping is available. The freezing that is applied to gain access initially can be shut off once the concrete block has been established. The excavation within the concrete block can be maintained indefinitely using timber cribs and does not require backfilling as stoping advances and excavation within the prepared block extends in outward directions. The method will afford a minimum disruption to the surrounding clay area and, assuming the concrete block is adequately designed and supported, could be kept open indefinitely.
_g_
Claims (13)
1. A method of constructing a concrete-lined horizontal gallery in an unstable subsurface, which method comprises:
(a) freezing a zone of unstable subsurface extending in a selected horizontal direction from an established gallery or shaft, said zone having preselected dimensions for accommodating said horizontal gallery in accordance with method steps defined subsequently herein;
(b) excavating a preliminary chamber having a non-collapsing frozen periphery from within a frozen perimeter of said zone, said preliminary chamber having dimensions selected to correspond to an outer perimeter of a non-collapsing concrete lining of said concrete-lined horizontal gallery to be subsequently formed in said preliminary chamber;
(c) completely filling said preliminary chamber with settable concrete;
(d) after said concrete is set, excavating a final chamber having a non-collapsing concrete periphery and gallery dimensions from within an outer perimeter of said concrete, thereby forming a non-collapsing concrete-lined horizontal gallery.
(a) freezing a zone of unstable subsurface extending in a selected horizontal direction from an established gallery or shaft, said zone having preselected dimensions for accommodating said horizontal gallery in accordance with method steps defined subsequently herein;
(b) excavating a preliminary chamber having a non-collapsing frozen periphery from within a frozen perimeter of said zone, said preliminary chamber having dimensions selected to correspond to an outer perimeter of a non-collapsing concrete lining of said concrete-lined horizontal gallery to be subsequently formed in said preliminary chamber;
(c) completely filling said preliminary chamber with settable concrete;
(d) after said concrete is set, excavating a final chamber having a non-collapsing concrete periphery and gallery dimensions from within an outer perimeter of said concrete, thereby forming a non-collapsing concrete-lined horizontal gallery.
2. The method of claim 1 wherein steps (a) to (d) are performed sequentially in two or more cycles to extend said horizontal gallery in stages.
3. The method of claim 2 wherein the horizontal gallery is extended to a preselected location remote from a deposit, thereby establishing a working gallery from which to mine the deposit.
4. The method of claim 3 wherein the working gallery is located above the deposit.
-Page 1 of Claims-
-Page 1 of Claims-
5. The method of claim 3 wherein the working gallery is located below the deposit.
6. The method of claim 1 wherein the established gallery or shaft is in stable subsurface.
7. The method of claim 1 wherein the freezing of step (a) is extended from an established gallery in stable subsurface which, in turn, extends from a shaft in stable subsurface.
8. A method of mining a deposit located in unstable subsurface, which method comprises:
(a) sinking a shaft in substantially stable subsurface at least to a depth from which a horizontal gallery may be extended partly through stable subsurface towards a preselected location in unstable subsurface for constructing a working gallery for the deposit;
(b) extending a horizontal gallery from said shaft towards said preselected location through substantially stable subsurface until intervening unstable subsurface is encountered;
(c) freezing a zone of unstable subsurface extending, from where said intervening unstable subsurface is encountered, in a horizontal direction towards said preselected location, said zone having preselected dimensions for accommodating an extension of said horizontal gallery in accordance with construction steps defined subsequently herein;
(d) excavating a preliminary chamber having a non-collapsing frozen periphery from within a frozen perimeter of said zone, said preliminary chamber having dimensions corresponding to an outer perimeter of a non-collapsing concrete lining of a gallery selected to be formed in said preliminary chamber;
(e) completely filling said preliminary chamber with -Page 2 of Claims-settable concrete;
(f) after said concrete is set, excavating a final chamber having a non-collapsing concrete periphery and gallery dimensions from within an outer perimeter of said concrete, thereby forming a non-collapsing concrete-lined gallery;
(g) sufficiently repeating steps (c) through (f) sequentially to advance construction of the horizontal gallery until a working gallery is provided at said preselected location; and (h) mining said deposit from said working gallery.
(a) sinking a shaft in substantially stable subsurface at least to a depth from which a horizontal gallery may be extended partly through stable subsurface towards a preselected location in unstable subsurface for constructing a working gallery for the deposit;
(b) extending a horizontal gallery from said shaft towards said preselected location through substantially stable subsurface until intervening unstable subsurface is encountered;
(c) freezing a zone of unstable subsurface extending, from where said intervening unstable subsurface is encountered, in a horizontal direction towards said preselected location, said zone having preselected dimensions for accommodating an extension of said horizontal gallery in accordance with construction steps defined subsequently herein;
(d) excavating a preliminary chamber having a non-collapsing frozen periphery from within a frozen perimeter of said zone, said preliminary chamber having dimensions corresponding to an outer perimeter of a non-collapsing concrete lining of a gallery selected to be formed in said preliminary chamber;
(e) completely filling said preliminary chamber with -Page 2 of Claims-settable concrete;
(f) after said concrete is set, excavating a final chamber having a non-collapsing concrete periphery and gallery dimensions from within an outer perimeter of said concrete, thereby forming a non-collapsing concrete-lined gallery;
(g) sufficiently repeating steps (c) through (f) sequentially to advance construction of the horizontal gallery until a working gallery is provided at said preselected location; and (h) mining said deposit from said working gallery.
9. The method of claim 8 wherein the working gallery is selected to be above the deposit.
10. The method of claim 8 wherein the working gallery is selected to be below the deposit.
11. The method of claim 8 wherein the freezing is turned off once hardened concrete has formed.
12. The method of claim 8 wherein step (h) is performed using raised bore stoping methods.
13. The method of claim 8 wherein in step (f) a Roadheading machine is used to achieve an acceptable thickness of said non-collapsing concrete periphery.
-Page 3 of Claims-
-Page 3 of Claims-
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2243016 CA2243016A1 (en) | 1998-07-14 | 1998-07-14 | Concrete block mining method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2243016 CA2243016A1 (en) | 1998-07-14 | 1998-07-14 | Concrete block mining method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2243016A1 true CA2243016A1 (en) | 2000-01-14 |
Family
ID=29409626
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2243016 Abandoned CA2243016A1 (en) | 1998-07-14 | 1998-07-14 | Concrete block mining method |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2243016A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102174892A (en) * | 2011-03-10 | 2011-09-07 | 贵州铸安矿山科技股份有限公司 | Rotary cutting type cross-cut coal uncovering method |
| CN107654234A (en) * | 2017-07-24 | 2018-02-02 | 广州地铁设计研究院有限公司 | A kind of construction method of subway tunnel crossing subway station diaphram wall |
-
1998
- 1998-07-14 CA CA 2243016 patent/CA2243016A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102174892A (en) * | 2011-03-10 | 2011-09-07 | 贵州铸安矿山科技股份有限公司 | Rotary cutting type cross-cut coal uncovering method |
| CN107654234A (en) * | 2017-07-24 | 2018-02-02 | 广州地铁设计研究院有限公司 | A kind of construction method of subway tunnel crossing subway station diaphram wall |
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