Wells – With explosive or gas generating means in well
Reexamination Certificate
2001-06-04
2003-01-07
Schoeppel, Roger (Department: 3672)
Wells
With explosive or gas generating means in well
C166S187000, C175S004520, C086S020150, C102S304000, C102S313000, C102S333000
Reexamination Certificate
active
06502631
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to relatively inexpensive borehole plugs formed from toy or sport balls typically used for play such as by children and/or in sporting events, the borehole plugs particularly being used to support stemming and/or explosives within a borehole to facilitate shattering of earth formations by detonation of explosives within one or more boreholes.
2. Description of the Prior Art
Mining and earth removal operations often employ methodology known in the art as presplitting, this practice involving the shattering of earth formations in a controllable manner to facilitate the removal of overburden to expose seams of material which are to be mined. Devices have previously been available in the art to “plug” boreholes drilled in patterns for the practice of presplitting. Such devices have been intended to suspend explosives and/or stemming within such boreholes. Devices have also been available in the art for suspending stemming and/or explosives within boreholes intended to facilitate production blasting by various methods common in the art. A discussion of the prior art can be found in U.S. Pat. No. 5,035,286 to Fitzgibbon, Jr. relative to prior art previously available in the mining and earth removal industries. This patent also comprises prior art relative to the present invention. Further, the disclosure of U.S. Pat. No. 5,035,286 is incorporated hereinto by reference. Further, the disclosures of U.S. Pat. Nos. 4,913,233; 4,919,203; 5,000,261 and 5,273,110 are also incorporated hereinto by reference, these patents having the same inventor as the present patent application and common ownership with the present patent application.
Also incorporated hereinto by reference is U.S. Pat. No. 3,357,193, also to Fitzgibbon, Jr., which patent discloses temporary closure devices for boreholes, the devices being formed as inflatable, tubular structures which are inserted in a deflated condition into the upper end of a borehole and inflated therein in order to temporarily close off the hole to prevent ingress of water, to prevent ice formation within the hole and to prevent blockage of the hole by undesirable material which can fall into an open borehole. The devices of this patent further act to prevent personnel from stepping into or falling into such holes with resulting injury.
On recognition of the value of the technology disclosed in the aforesaid patents, the industry has attempted to identify inexpensive alternatives to the particular inflatable devices described in the aforesaid patents, the devices of the patents being formed of materials and through the use of methodology which has resulted in inflatable borehole plugs of exceptional reliability. The borehole plugs provided according to the aforesaid patents were found to be rapidly and conveniently useable in field blasting operations, the said borehole plugs being repositionable as desired within a borehole in the event that initial positioning within the borehole was not satisfactorily accomplished or the initial position was not the most desirable location for the plug. While the borehole plugs configured according to the aforesaid patents are relatively inexpensive in view of their value in the shattering of earth formations, practitioners in the art have continually attempted to form such borehole plugs from exceedingly cheap materials, such as the “rubbers” used to manufacture ordinary playground balls or the like. While certain of these inflatable playground balls have functioned within certain environments at least a certain percentage of the time, these insubstantial devices have not proven to be satisfactory due to the large percentage of these devices which lose pressure once inflated within a borehole and thus have to be replaced if the user is fortunate enough to have avoided placement of stemming or explosives on top of such devices. Failure of these prior devices to maintain pressure once stemming or explosives or the like have been deposited within a borehole results in loss of the borehole and any value of the explosives and/or stemming or the like in subsequent blasting operations. The present invention particularly intends the fabrication of borehole plugs formed of plug wall materials of lesser quality than has previously been permissible with necessary reliability, the borehole plugs according to the invention being improved through reinforcement which permits the present plugs to function properly and with desired reliability within the harsh confines of a borehole wherein walls of the borehole contain irregular and jagged rock and earth surfaces and projections from said surfaces. The present devices thus constitute a significant and substantial advance in the art.
SUMMARY OF THE INVENTION
The inflatable devices of the invention suspend explosives and/or stemming materials within boreholes formed in earth formations to allow practice of methods for shattering the earth formations to effect presplitting or earth removal inter alia. The inflatable devices of the invention are positioned within boreholes in a deflated condition and are inflated at the desired locations within the hole to seal or “plug” the hole for support of explosive columns and/or stemming columns. The inflatable devices are formed according to the invention of common toy or sport balls of differing diameter and which are further provided with a reinforcing scrim disposed over inner wall surfaces thereof, the structure being completed by provision of an inner elastomeric layer which acts along with the toy or sport ball outer layer to sandwich the scrim therebetween the thus reinforce the inflatable device so formed. Use of the toy or sport ball itself without further improvement according to the invention results in production of an inflatable device essentially formed of a “rubber” material or other elastomeric material which is extraordinarily susceptible to deflation within the environment of a borehole, it being necessary for an adequate inflatable device to support columns of explosives and/or stemming which can weigh many tons. Even though the toy or sport ball itself may be thicker than the materials used to form the inflatable devices particularly described in U.S. Pat. No. 5,035,286, for example, these toy or sport balls are not adequate to the intended use since said balls do not have the capability to stretch to a degree sufficient to cause the inflatable device so formed to be firm within the borehole and yet resist continued stretching, particularly in directions along the longitudinal axis of the borehole which causes an unacceptable number of such devices to fail.
While inflatable devices configured according to the invention can be formed with gas or foam generating materials sealed within said inflatable devices, it is preferred to form the inflatable devices of the invention with valves which allow inflation of the devices through hoses connected to the valves while the devices are in place within the boreholes. Valves such as tire valves, oral valves, needle valves and the like are useful. However, it is to be noted that valves such as needle valves are self-sealing and are readily connected to and disconnected from an air line such that the device can be lowered down into a borehole, inflated and then readily released from the air line. The use of certain types of valves, such as oral valves, typically require a protective flap when used with the devices of the invention.
The devices of the invention can be formed in differing sizes to accommodate boreholes of differing diameter. When used for presplitting with holes of relatively smaller diameter, columns of explosives or stemming are of lesser total weight than is the case with presplitting and production boreholes of diameters of nine inches or greater where explosive or stemming columns can weigh substantially more.
The scrim employed for reinforcement of the present inflatable devices is preferably chosen to be a nonwoven material formed of filamentary elements having high tensile st
Darnell Kenneth E.
Schoeppel Roger
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