US-12624612-B2 - Inflatable down hole bag

US12624612B2US 12624612 B2US12624612 B2US 12624612B2US-12624612-B2

Abstract

An inflatable down hole bag for insertion into a blast hole, comprising: a sealed inflatable body; a first substance within the sealed inflatable body; a plurality of tablets separated from the first substance within the sealed inflatable body; and a release for allowing the first substance to contact the tablets; wherein the tablets comprise a second substance, and wherein contact between the first substance and the second substance causes an inflation fluid producing reaction within the sealed inflatable body, thereby inflating the inflatable body, wherein the tablets are configured to fragment after contact with the first substance.

Inventors

James Matthew Richard FITZSIMONS
Nicholas Bodley
Jamie Smith

Assignees

MTI GROUP PTY LTD

Dates

Publication Date: 20260512
Application Date: 20230523
Priority Date: 20220523

Claims (16)

1 . An inflatable down hole bag for insertion into a blast hole, the inflatable down hole bag comprising: a sealed inflatable body; a first substance within the sealed inflatable body; a plurality of tablets separated from the first substance within the sealed inflatable body; and a release for allowing the first substance to contact the tablets; wherein: the tablets comprise a second substance, a third substance, and a binder; the inflatable down hole bag is configured to cause an inflation-fluid-producing reaction within the sealed inflatable body upon contact between the first substance and the second substance, thereby inflating the inflatable body; and the third substance is configured to cause the tablets to fragment.
2 . The inflatable down hole bag according to claim 1 , wherein the tablets are configured to start the inflation-fluid-producing reaction upon contact with the first substance.
3 . The inflatable down hole bag according to claim 1 , wherein the second substance comprises a reagent.
4 . The inflatable down hole bag according to claim 3 , wherein the tablets are configured to fragment upon expansion of the third substance once sufficient fluid has been absorbed.
5 . The inflatable down hole bag according to claim 1 , wherein the third substance is configured to absorb fluid and expand.
6 . The inflatable down hole bag according to claim 1 , wherein the third substance comprises a disintegrant.
7 . The inflatable down hole bag according to claim 6 , wherein the disintegrant contains starch.
8 . The inflatable down hole bag according to claim 1 , wherein the tablets are of substantially homogenous composition.
9 . The inflatable down hole bag according to claim 1 , wherein the tablets further comprise a lubricant.
10 . The inflatable down hole bag according to claim 1 , wherein the inflatable body comprises a pocket for holding the first substance prior to contact with the second substance.
11 . An inflatable down hole bag for insertion into a blast hole, the inflatable down hole bag comprising: a sealed inflatable body; a first substance within the sealed inflatable body; a plurality of tablets separated from the first substance within the sealed inflatable body; and a release for allowing the first substance to contact the tablets; wherein: the tablets are configured to cause the bag to inflate according to a selected inflation profile defined by physical properties and composition of the tablets, the inflatable down hole bag is configured to start an inflation-fluid-producing reaction when the tablets contact the first substance, the tablets comprise at least two different types of tablets, wherein two types of the at least two different types have different inflation characteristics, and wherein the two types are selected according to a desired inflation profile of the bag; and the tablets further comprise a binder.
12 . A tablet for use in an inflatable down hole bag for insertion into a blast hole, the tablet comprising: a reagent; and a disintegrant, wherein: the reagent is configured to cause an inflation fluid producing reaction upon contact with acid, the disintegrant is configured to causes the tablet to fragment, physical characteristics of the tablet are selected according to a desired duration between commencement of the reaction and commencement of the fragmentation of the tablet, and the tablet further comprises a binder for binding the reagent and disintegrant together.
13 . The tablet according to claim 12 , wherein the binder causes the duration to be extended.
14 . A method of fabricating an inflatable down hole bag for insertion in a bore hole, the method comprising: at least partially filling the bag with a first substance, preparing a mixture, the mixture comprising a second substance, a third substance, and a binder, compressing the mixture in a die to form at least one tablet, locating the at least one tablet in the bag separated from the first substance, and sealing a sealed inflatable body of the inflatable down hole bag.
15 . The method according to claim 14 , further comprising including in the mixture a lubricant.
16 . The method according to claim 14 , further comprising selecting the composition of the mixture according to a desired inflation profile of the bag.

Description

FIELD OF THE INVENTION The present invention relates to an inflatable down hole bag for stemming a blast hole to confine energy released from an explosive charge. BACKGROUND In underground and surface mining, blasting is commonly used, in which explosive charges are detonated inside a bore hole at a desired depth. Where a blast hole is left open, explosive energy can be lost through stemming ejection, reducing the efficiency of the blast. To counter this loss of energy, blast holes are often plugged or stemmed by inserting a device to fill the hole between the surface and the explosive charge, thus preventing the loss of energy and increasing the effectiveness of the explosive charge. Such devices include plugs of clay or foam, or inflatable blast hole plugs, examples of which are provided by the present applicant. An example of an inflatable blast hole plug is a bag suitable for insertion into the blast hole, the bag containing two substances that, when mixed, release a gas to cause expansion of the bag, thus filling the bore of the blast hole. Inflatable blast hole plugs are activated by the operator to cause the substances to mix and the gas to release, and then lowered (or raised) into a hole to a sufficient height to block the hole. Once the release of gas starts, it cannot be stopped or slowed and accelerates as an uncontrolled chemical reaction, meaning that the operator will only have a limited time to place the bag at the correct height. Where the time is insufficient the bag will become lodged and must be removed by the operator perforating and removing the bag. Conversely, an especially slow, or delayed, reaction is undesirable as an operator must either wait for the bag to inflate sufficiently to support its own weight or take action to hold the bag in position. A blasting operation can be undertaken on a large number of blast holes simultaneously, and the preparation of each blast hole can take significant time and must be performed by suitably qualified operators. As the blast hole plugs must be inserted into multiple blast holes, any improvement directed to increasing the speed or efficiency of preparation is desirable. It is against this background that the invention is presented. The following discussion of the background art is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge as at the priority date of the application. Throughout the specification unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Throughout the specification unless the context requires otherwise, the word “include” or variations such as “includes” or “including”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. SUMMARY OF INVENTION According to a first aspect of the present invention, there is provided an inflatable down hole bag for insertion into a blast hole, comprising: a sealed inflatable body;a first substance within the sealed inflatable body;a plurality of tablets separated from the first substance within the sealed inflatable body; anda release for allowing the first substance to contact the tablets;wherein the tablets comprise a second substance, and wherein contact between the first substance and the second substance causes an inflation fluid producing reaction within the sealed inflatable body, thereby inflating the inflatable body, wherein the tablets are configured to fragment after contact with the first substance. According to a second aspect of the present invention, there is provided an inflatable down hole bag for insertion into a blast hole, comprising: a sealed inflatable body;a first substance within the sealed inflatable body;a second substance in tablet form separated from the first substance within the sealed inflatable body; anda release for allowing the first substance to contact the second substance;wherein contact between the first substance and the second substance causes an inflation fluid producing reaction within the sealed inflatable body, thereby inflating the inflatable body, wherein the tablets are configured to fragment after contact with the first substance. According to a third aspect of the present invention, there is provided an inflatable down hole bag for insertion into a blast hole, comprising: a sealed inflatable body having first and second separable portions,a first substance within the first portion,a second substance in tablet form in the second portion,a release for allowing the first and second substances to contact one another;wherein contact between the first substance and the second subs