Note: Descriptions are shown in the official language in which they were submitted.
CA 02690233 2010-02-12
Drift Saver Patent A location
Background to the Invention
Valuable minerals are contained in underground deposits which are referred to
as Ore bodies.
Before mining operations can commence, a number of underground excavations
must be created
at varying level intervals. These levels are often referred to as overcuts and
undercuts, which
gain access to the mining of desired ore body panels.
These panels are mined in varying sequences of excavating and backfilling.
After each panel is
mined it is then backfilled with waste material such as waste rock, cemented
tailings, cemented
rock fill, paste fill or other mixtures of hydraulic backfill. Prior to
backfilling and strong
barricade such as a shotcrete fence must be constructed at a safe distance
back from the mined
panel in the undercut. This barricade contains the backfill in the mined
stope. However with
these current methods, once the backfill has cured mining operations must
remove the backfill
fence/barricade and re-excavate back through the fill to expose the next
panel. This current
method is very time consuming and expensive.
There remains a need for a more economical and efficient way of constructing a
Backfill fence
and to eliminate the need for re-excavating the undercut.
The present invention is an inflatable device which is referred to as a DRIFT
SAVER. The Drift
Saver is an inflatable device which is placed in the undercut at a
predetermined location. Once
placed at the correct location it is hooked to an air supply and is inflated
to the desired pressure.
Once inflated the Drift Saver acts as a 1. Backfill fence or barricade to
contain the backfill in the
desired stope and 2. Fill the void area from the traditional backfill fence to
the brow of the mined
stope to eliminate the need of re-excavating the undercut.
Summary of the Invention
The Drift Saver is comprised of a single or multiple inflatable cells, housed
in a protective
shroud.
The present invention provides a method of mining an ore body panel in the
following steps.
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CA 02690233 2010-02-12
1. Placing the Drift Saver in the undercut at desired location.
2. Inflating the Drift Saver to form a strong, tightly sealed barricade which
will occupy the
void from the current backfill fence location to the existing brow.
3. Maintain the void during the backfill cycle.
4. Once the backfill has cured, the Drift Saver is deflated and removed for
inspection and
future use.
In one form the advantage of the Drift Saver is that it is inflatable and can
be transported to the
undercut of the stope in a deflated condition and inflated once in position.
This also allows the
Drift Saver to be removable and reusable.
Alternatively, the Drift Saver is filled with an incompressible fluid (such as
water) and once the
backfill has cured it is deflated, removed and reused in future applications.
In one form, the Drift Saver is capable of withstanding forces up to 40psi of
internal or external
forces.
The Drift Saver comprises of a fluid-tight protective shroud having at least
one cell which is
isolated from the surrounding atmosphere and is capable of retaining a fluid
under pressure.
To resist damage from occurring during inflating/deflating and removal, the
protective shroud
and internal inflation cells may be constructed of a tear-resistant material.
In one form, the protective shroud is constructed from woven materials such as
polypropylene/polyethylene or PVC like materials.
In one form, the Drift Saver is dimensioned 0% to 20% larger than the
excavated dimensions to
fill all available voids in the excavation to form a tight seal around the
surrounding host
rock/material or shotcrete.
Single or multiple inflation line(s) are used to regulate and monitor the
pressure within the Drift
Saver during step 2, by the use of a pressure regulator. The pressure
regulator provides feedback
to the operator of the internal pressure and also provides an indication of
backfill pressure.
The Drift Saver is comprised of single or multiple inflation cells housed
inside of a protective
shroud. The larger the excavation the more inflatable cells will be required.
In large excavations, greater than 9 square meters, the protective shroud will
contain reinforcing
straps/webbing running horizontally and vertically around the shroud to add
extra strength to the
Drift Saver.
Preferably, the inner cell(s) are constructed of a material having a low fluid
permeability. In one
form, the inner cells may be constructed of one or more materials selected
from the group
comprising: polyethylene, polyurethane, polypropylene, latex, reinforced PVC,
PVC, coated or
co-extruded plastic materials which have suitable strength and suitable low
gas permeability.
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To provide redundancy in the event of a puncture, the Drift Saver may comprise
of multiple
fluid-tight inner cells arranged inside the protective shroud. In one form,
the Drift Saver is
provided with a surplus of inflatable cells over and above the number required
to fill the volume
occupied by a fully inflated Drift Saver. Each of the cells may be
independently collapsible.
In one form, the Drift Saver is comprised of multiple cells in the protective
shroud and each cell
is configured to independently receive fluid from a fluid delivery system.
Alternatively, each of
the inner cells may be in fluid communication such that fluid supplied to the
cavity of one of the
inner cells is receivable within the cavity of each inner cell whereby all
cells can be
simultaneously inflatable and collapsible.
According to the to the aspect of the present invention, there provides an
inflatable device the
Drift Saver as herein described with reference to an as illustrated in the
accompanying drawings.
Brief Description of the Drawings
In order to provide a more detailed understanding of the nature of the
invention several
configurations of the present invention will now be described in detail, by
way of example only,
with reference to the accompanying drawings, in which:
Figure 1 is a side view of the mine showing the location of an ore body, an
upper level (over cut)
and lower level (under cut) and the deployment of the Drift Saver within the
undercut of a stope.
Figure 2 is a partial cross-section view of a single celled Drift Saver of the
present invention in
which the cell is partially inflated and comprises of a single housing which
is monitored by a
pressure regulator.
Figure 3 is an isometric view of the present invention illustrating the
provision of retention straps
for strength and rigidity improvements.
Figure 4 is a partial cross-section view of a second configuration of the
Drift Saver in which it
comprises of multiple inner cells arranged inside a single protective shroud
connected to a
pressure regulator, controller and inflation line.
Figure 5 illustrates the Drift Saver of Figure 4 in a deflated condition for
ease of transport.
Figure 6 illustrates current practise of backfilling a stope without the use
of the Drift Saver. This
drawing shows a typical fill fence location of 5m back from the existing brow,
but this location
varies from site to site. Because the fill fence is not located right at the
brow, the fill fence and
fill must be re-excavated to expose the entire panel, prior to mining the next
panel in sequence.
This is the starting location for the Drift Saver, once inflated it will
occupy the entire void (from
fill fence to the brow). Thus saving the customer from expensive rework,
material handling and
from disrupting the operations down stream.
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