CA2075104C - Process and device for the exploitation of subterranean deposit by means of a tunnel borer - Google Patents

Abstract

The process is intended for the exploitation of deposits underground whose extraction is made difficult by the radioactive and / or toxic character of the deposit and / or by geotechnical conditions. We constitute, by injection of hydraulic and / or freezing binder, a box (C) watertight confining all or part of the deposit and draining possibly the deposit; we go right through deposit by direct digging of a first tunnel using a tunnel boring machine; we return the tunnel boring machine after crossing of the deposit and we directly dig a tunnel adjacent to the first, and so on; if the deposit contains a radioactive, dangerous or toxic product, the material extracted into pulp as and when slaughtered and it is removed by hydraulic transport.

Description

PROCEDURE AND DEVI'I'I ~ F 'z?' EXPLOITATE: LON OF UNDERGROUND DEPOSIT
BY TUNNELIER
The invention relates to methods and devices of exploitation of underground deposit ds ~ nature such as the cost of extraction per ton goes to the background.
The invention finds a particularly application important in the extraction of ores from substances whose toxicity or radioactivity are such that it it is not possible to implement the classi ques of mining, especially when problems in addition to radioactivity in addition to toxicity.
As a particularly representative example, we can cite the exploitation of very uranium deposits high content, where the level of radioactivity excludes traditional methods involving the presence of staff permanently on the face, but where a ~ ex-high pull is not prohibitive because 31 is offset by grades of up to 100 kg per tonne, or more.
A similar problem arises in the case of deposits with a very high content of a high value product merchantable, relatively thick, but occurring in particularly difficult geotechnical conditions, such that know dos lithostatic and hydrostatic pressures very raised in deconsalidated land.
Mention may also be made, as an appellation of the invention, removal, for decontamination and / or safe storage of long-term substances women who do not necessarily have a market value but that it is imperative to eradicate.
S5 This last case pewt for example meet in no contamination of the polluted basement of a facility nuclear.

2 The invention therefore aims to provide a .pr yielded from exploitation of underground deposit whose ex ~ trac-Lion is made difficult by the radioactive character and / or toxic from the deposit and / or by geotechnical conditions, when the market value of the deposit and / or the need absolute to extract it make the cost of the operation secondary ration for each tonne extracted.
For this purpose, ~. ' invention proposes; including a pro assigned according to which. we eonsti ~ kills, by injection of binder hydraulically and / or by freezing, a waterproof box con withering all or part of the deposit and eventually draining-lie the deposit; we cross right through the deposit by direct digging of a first tunnel using a tunneling machine; we return to the 1st tunnel boring machine after crossing ~ Iu ga-sowing it and we directly dig a tunnel adjacent to the mier, and so on; and, if the deposit contains a radioactive, dangerous or toxic product, the material is reduced material extracted into pulp as and when slaughtered and it is removed by hydraulic transport.
In the case of difficult terrain, presenting a risk of landslide we cover the gallery with canopies immediately behind the TBM. Once a -tunnel completely formed, it can be immediately backfilled to participate in absorbing the thrust of the terrain.
Depending on the nature of the difficulties encountered in the operation, the process will be more or less complex.
When the difficulties encountered are essentie3.-lament of geotechnical nature lithos ~ tatic pressures and hydrostatic), causing large amounts of water aunts, the constitution of a barrier by coating â
with the help of segments connected ~ aar by seals, solves the problem. In the case of materials radioactive, the measurements above deviate from ~ ~ name many problems. gamma radiation of external origin

3 ~ is absorbed by the concrete of the segments and the dupe of the ton-bind. The overpressure of the tunnel reduces radon inputs. Hydraulic transport can take place through a pipe embedded in a protective base tion against the gamma radiation of the matö: riau extract.
The conditions of use of the tunnel boring machine, for the using the process according to the invention are extremely unusual and seem at first sight to be nonsense nonsense mique. A tunnel boring machine is indeed planned to dig ga Very long lines in continuity. On the contrary, the process following the invention involves long periods of inactivity after completion of each tunnel. But clear consideration becomes secondary when the market value of the extracted material or the absolute necessity to eliminate it requires extraction because none of the solutions known, more economical, only applicable in cases 18 mentioned above.
The invention also provides a device operating underground deposit including a tun-nelier with point attack by telescopic arm excavator swivel spike, separable into at least three long sections longitudinal, carrying a grinder and a pulverization pump eg slaughtered material for pulp shipment to a hydraulic transport line and having, in its rear section, a device for positioning you-tunnel lining evenings.
The tunneling machine, for the extraction of strong ores-radioactive, has a skirt of sufficient thickness to reduce the intensity of the radiation. I1 is planned for can be returned to a room after crossing deposit of the deposit, either by rotation of 180 ° around a 80 vertical axis, either by disassembly and then reassembly. The three sections can themselves be divided into sectors about 120 ° each, to facilitate the operations of transfer in the latter case.
The invention will be better understood on reading the description which follows of a particular embodiment, given by way of nonlimiting example. The description is

4 refers to the drawings which marked it, in which - Figure 1 is a sohëma of prine ~ ipe in perspective tive, showing the operations for preparing a .fraction of the deposit, before slaughter FIG. 2 is a schematic sectional view, showing the digging of a first 'horizontal tunnel â
across the deposit has - Figure 3, similar to 1a aigure 2, mantre la juxtaposition of drilled, coated and filled tunnels at during operation;
- Figure 4 is a schematic view, in section in a vertical plane, showing the main constituents of a tunnel boring machine constituting a particular mode:
realization of the invention r - Figure 5 is a cross-sectional view of the coated tunnel 1 "behind the TBM, when setting up work of the method according to a particular mode of realization ~ tion of the invention.
The process which will now be described is in particular usable for the exploitation of an underground deposit of very high grade uranium ore, occurring under in the form of an elongated vein, in a deconsolidated rock, under very high lithostatic and hydrostatic pressure.
As an example of a deposit presenting these ca ractëris ~ ticks; we can cite that of CTC13R LAKE, SASKATCHE ~ 1 ~ 1N, Canada, which has a grade of 100 ~ g per tonne on average, allowing operation at a very high rate low of the order of 200 tonnes per oven. The rock encais sante is a sandstone sandstone, with water inflows abundant. The exploitation must be done under a pressure lithostatic of the order of 80 bars and a hydro-static of the order of 45 bars. The deposit presents a (elongated weapon, with a width of T in the order of a hundred of meters.
S5 The first operation to be carried out before attacking the deposit, aims to form, autoLar of a longitudinal fraction the deposit, a watertight box that it will be possible to

5 drain, the walls of which are made of conso-lidëes by freezing e ~ t / or cement slurry infection, each caisson enveloping the deposit as close as possible, practically at a distance of: a few meters.
To do this, we first of all carry out infra-classical structures for access to deposits, the depth of which Deur is of the order of X50 meters in the 1st case of CïGAF ~
LAKE. We dig the access and aeration wells and put energy, ventila ~ tason installations in place, extraction, etc, then we dig the horizontal galleries access to the deposit as well as horizontal galleries infrastructure. Among these gallery of infrastruotur ~, at least two I2 extend in the direction of elongation of the deposit, roughly parallel to the edges of the latter.
girls can be. near the upper level of the gise-is lying. Another I ~ at least is at a few meters below the deposit.
Two parallel cuts 16 are then dug at from gallery I4, at distances which will depend on The nature of the terrain but will generally be of the order of the ten meters.
From the different galleries 12 and 14 and re-I6 lids are then drilled with vertical holes 18 intended to receive the freezing beams and possibly lances of in ~ eotion of cement pouring. The holes ver-ticals drilled from the cuts 16 which cross the ge In any case, will be used for freezing.
At the end of these operations and the freezing at from two cross-sections, we see that we have created a callus its surrounding a slice of the deposit. This box, whose periphery is shown in C in FIG. 2, can then be drained, its central part was not frozen. It's in that part that the extraction will have.
The slaughter ~ inside the box is carried out by repetition of the same sequence. From galleries 12 on ~~, ~ c ~ _ ~. ' digs two inclined planes 20 of access to r ~ rooms -turning 22, through the frozen rock. These rooms of turning 22 (figure 2) are formed at a distance from the mine-itself, so that the level of radioactivity there remains acceptable for human intervention. A tunneling machine, such as that which will be described later, is assembled in one of the turning chambers 22, located just above from the base of the deposit. The tunnel boring machine is then used vre and directed, horizontemewt or obliquely by .report â ..
gallery 12, towards the other turning chamber. I1 crosses the curtain of sterile material, then the deposit to the opposite turning chamber 22. In this room it can be checked and refurbished, by replacement elements most susceptible to wear or breakdown: I1 is then moved back on the inclined plane to the gallery 12. he first tunnel is backfilled. A new inclined plane is formed up to a turning chamber located immediately next to the previous one. The inclined plane and the previous room are backfilled for example using materials slaughtered lice form the new inclined plane.
he can then be advanced to dig a second tunnel.
Once all the successive tunnels in the section at the basic level B (figure 3) were dug then repacked layered, lower inclined planes are made to successively process the higher levels of the deposit.
Thanks to the prior containment in a sealed box, the problems of water supply are eliminated. Provided line the tunnel as the 1st tunnel advances tie by segments, to provide joints between rings successive and to use a sealed tunneling machine, the effect of freezing is completed and allows to work in ter-rain fragile, at great depth, with waxes ve-.
bare of pressurized water.
while a case is being treated, 1 ~ case following can be prepared by possible lengthening of the ga-lines 12 and 14, digging of cross sections 1C ~ e ~ t freezing and / or lice injection build up a new box.
We will come back to the process part later concerning the actual attack on the ore.
The TBM used pewt have the cons'ti'tution of principle shown in Figure 4, comprising three sections longitudinal 28, 30 and 32 can be assembled and disassembled.
Each of these sections can itself be provided to be detachable in several angular sectors, three per example, in order to reduce the size and weight of inseparable components during transport. For the same reason, we will generally use a compact tunnel boring machine, a ~ amt a reduced skirt diameter, for example four about meters. Each of the sections may also have a short length, for example around 1.50 m.
The front section comprises a skirt and constitutes a adjustable kit by cylinders 34, closed at the back by a watertight bulkhead fitted with observation windows this partition can also belong to the section median 30). The section 28 carries a slaughtering device é
punctual attack, constituted in the case illustrated by a excavator with telescopic arm 36 terminated by a crown attack 38 which can be brought into projection not relative to the section 28. The excavator is lined with a breaker block 39, allowing them to be reduced to, if necessary, size of a few centimeters and a device of injeo-water under high pressure. The ore cut is thus brought to 1 ° state of fragments of sufficiently small size ble to be driven by a conveyor, as we will see glus away.
The front section 28 is advantageously provided for receive a removable diaphragm 41, allowing, after re-pull the telescopic arm 3b, isolate the device of slashing of the working face to authorize an iwterven--mechanical horsefly. This gent diaphragm connects to a helmet security 40 provided d of the upper part of the section.
The median section 30 constitutes the pusher. It is "
accordingly goes, inside the skirt, a row of hydraulic cylinders ~ 2, twenty four in number for example, whose plunger 44 is intended will take support on the segments already in place. The section carries also an ore recovery conveyor, consisting in the case illustrated by an oblique extraction screw 46.
This screw goes up the fragments in a crusher ~ 8 which reduces them to a sufficiently small particle size for allow transport in pulp. A mixing device circulation pump-feeder 50 picks up the ore crushed and 1 ° brings, through a non-return valve 52, to the entry of a tube 54 connecting with a pipe transport. The central section 30 can also contain a hydraulic unit 56 supplying the fluid under pressure required for the operation of the cylinders, pump excavator and possibly screws transport, crusher and pump.
The rear section 32 also has a skirt seal 58 intended to slide around the last you evening in place and sealing. She peaa ~ t equal contain an erector of icing of the segments, which will not be described because it can have a constitution ~ 5 classic.
In the illustrated embodiment, the pusher is planned to set up successively, after re-traction of the divers 44, the segments 62 brought by a 64 hoist carried by a beam fixed to the crowns of you-evenings as 1 ° advanced. The "little" segments wind have a provision of the kind shown in figure 5, that is to say, include five segments, properly speaking, numbered from 1 to 5, a key 68 and two counter keys 70.
The hoist can be provided to also set up places sections 72 of slab, each section having a length equal to that of a yousoix ', destiraës to constitute a flat floor and to delimit passages. One of these passages can receive a pipe i ~ de ~ transpor ~ t de mid nerai, connectable to a telescopa'Lque 7ô dm connection tube with the tube 54. Other passages 78 may constitute technical channels, for example; receiving cables.
Depending on the nature of the ore to be extracted, pre-more or less important additional guarantees are taken. In particular, we can interpose between you-evenings of a crown or halo, between successive crowns and between the last crown and the skirt 38, a tight seal che with water, avoiding infil-tracions and, in uranium mine, invasion of the tunnel coated by radon dissolved in water. A second joint, by a lead sheet, can be provided to absorb the rayon gamma ment coming from the host rock, with which there is in no case direct communication. Holes 80 infection can be provided in the segments in square.
An airlock is advantageously provided at the entrance to the gallery, in the barren rock. This allows the gallery in overpressure and further thwart the invasion by radon from the ore.
At the Gour $ of the advance of the TBM, the order, except in the event of an incident, does not require the presence of personnel inside the tunnel. A video camera can hearth provided in the central section to film the front of cut. Order staff can then stay in the turning chamber. The presence of staff is not only to lay the segments, at the end of a advance corresponding to the length of the segments. This phase lasts less than an hour per shift. It takes place while the staff are protected by the crowns of ~

lo segments already in place and by the steel of the skirt of the tunnel bind. Segments of about trewte centimeters of epals-give satisfactory protection. Driving in steel contained in slab "72 provides protection against the radiation of the pulp chinerai driven by water in tubes 42 and ~~ and line '7 ~.
Each intervention by the TBM is low duration, maintenance performed at each passage in a turning chamber makes the risk of breakdown very low corn. However, if necessary, the diaphragm of the part before pewt to be set up quickly and mechanically, under the supervision of a worker who stays in the middle section. The diaphragm then isolates the compartment contained in the front section of the front cut. After equipment decontamination and aspiration radon in the compartment, an operator can enter this compartment through a watertight door provided in the partition and perform the necessary intervention to be.
When it comes out of the ore, the TBM crosses some sterile before arriving at the return chamber-ment. The sterile slaughter already causes cleaning of the front structures and skirts. This cleaning can be supplemented with water decontamination:
Once the TBM is in the return chamber we turn it 1g0 ° to drill a new tunnel in reverse. The turnaround can be done in a way simple, by providing a hub in the room turnaround. The reversal can also take place ~ 0 by dismantling in sections, then reverse reassembly. As example, we can indicate that a tunnel boring machine of four meters Ires of diameter with punctual attacks by diagonal crown mantée easily allows a slaughter of 10 depending on the terrain tonnes per hour and a feed speed of 0.20 m / hour.
The slab sections can themselves have a width two meters fifty and receive a pipe of transport of aewt fifty millimeters in diameter.
The strict stacking of circular tunnels left in place about 9 ~ of the deposit. In: realizes the device slaughter beats an area higher than the tunnel section tying and overcrowding is enough to exploit the deposit almost completely.

Claims (10)

1. Method of operating an underground deposit by tunneling machine, comprising the steps of:
(a) cross right through the deposit by digging direct from a first tunnel using a tunnel boring machine;
(b) return the tunnel boring machine after crossing the deposit and directly dig a tunnel adjacent to the first one, and (c) repeating steps (a) and (b);
and, if the deposit contains a radioactive product, dangerous or toxic, reduce the material extracted to pulp as slaughter and evacuate by transport hydraulic. 2. Method according to claim 1, comprising a tunnel lining step with segment crowns behind the TBM. 3. Method according to claim 2, comprising a step of linking the segments with each other and with a skirt of the tunnel boring by watertight joints. 4. Method according to any one of claims 1 to 3, having a step of isolating the tunnel by an airlock and putting the tunnel under overpressure. 5. Method according to any one of claims 2 to 4, comprising the step of removing the material extracted by hydraulic transport in a pipe to a tube retractable (76) provided in the TBM and sections of pipe (74) contained in slabs (72) put in place on the basic segments. 6. Method according to any one of claims 1 to 5, characterized in that after crossing the deposit the tunneling machine returned to a turntable in a turning chamber (22) or disassembled then reassembled. 7. Device for the exploitation of underground deposits, including a tunneling machine with occasional attack by excavator with adjustable telescopic arm, separable into at least three longitudinal sections (28, 30, 32), carrying a grinder (48), a pulping pump for the slaughtered material and sending in a hydraulic transport line (42, 44, 74) and a device for installing segments (62) of tunnel lining. 8. Device according to claim 7, characterized in that the 1st front section (28) contains the excavator and is separated by a bulkhead from the middle section (30) which comprises a lifting conveyor, the crusher (48) and the pump and in that the rear section (32) contains a erector for the installation of prefabricated segments. 9. Device according to claim 7 or 8, characterized in that the middle section contains a ring of jacks passage hydraulics (42); a recovery conveyor (46) ore to the mill (48), said pump and a tube (54) telescopic connection with said pipe. 10. Device according to claim 7, 8 or 9, characterized in that the front section (28) is provided for receive a diaphragm and is separated from the middle section by a bulkhead.