US2204906A - Method of sinking a shaft - Google Patents

Description

UNITED STATES Search com PATENT OFFICE METHOD F SINKING A SHAFT John Branner Newsom, Nevada. City, Calif., as-

signor to Idaho Maryland Mines Corporation,

San Francisco, Calif.,

Application August 29,

8 Claims.

This invention relates to a mine shaft and has for its object the provision of a method of sinking a mine shaft of any given diameter by progressively enlarging a drilled shaft of relatively small diameter from the surface of the ground to any desired depth.

In carrying out this method a shaft of relatively small diameter is first drilled by the core drill shown in my United States Letters Patent No. 2,090,304 of August 1'7, 1937. After this has been done the ground surrounding the drilled shaft is divided into successive layers or benches by drilling rings of bench holes into the ground. A bucket is then secured and sealed within the drilled shaft below the level of the first bench, and dynamite or other exposive inserted into the bench holes dening the first bench and set oif, whereupon the ground forming the first bench is made to drop into the bucket. Following this, the bucket is raised to the surface, its contents disposed of, and then it is lowered, secured and sealed within the drilled shaft below the next succeeding bench, whereupon the operation is repeated until the drilled shaft has been enlarged to the desired depth.

To illustrate my invention more clearly, reference is made to the accompanying drawing, wherein:

Figure 1 is a vertical` section of drilled shaft showing successive layers of benches formed by radially disposed bench holes.

Figure 2 is a section taken on the line 2-2 of Figure 1.

Figure 3 is a vertical section similar to that shown in Figure 1 but with a bucket secured and sealed within the drilled shaft beneath the uppermost bench.

Figure 4 is a vertical section showing a drilled shaft and benches formed by vertically disposed bench holes.

Figure 5 is a detail showing the method of sealing the bucket within the drilled shaft.

Figure 6 is a vertical section taken through the lower portion of the bucket and showing the meansfor locking the bucket Within the drilled shaft'.

As briefly outlined above and as diagrammatically shown in Figures l, 2, Iand 3, a shaft l is first drilled to any desired depth, as for example by the core drill shown in my issued Patent No. 2,090,304. This having been done, a series of platforms 2, 3, and 4, spaced about eight feet apart, is-lowered into the drilled shaft. Drillers standing on these platforms drill concentric rings of radially and upwardly extending bench a corporation of Nevada 1938, Serial N0. 227,236

holes 5 into the ground surrounding the drilled shaft, for the purpose of defining layers or benches 6. The rings of holes 5 should be spaced about two feet apart and the outer ends of the holes 5 should approximately define the outer limits to which it is desired to enlarge the drilled shaft I. The drills used for drilling the holes 5 have been diagrammatically indicated at l. A bucket 8 is then lowered into the drilled shaft by the cable 9 and chains II to a point somewhat below the rst bench B and sealed and secured therein. For the purpose of sealing the bucket to the Walls of the drilled shaft I, resort may be had to a heavy rubber pneumatic tire l2 secured to the upper end of the bucket and provided with a heavily armored valve I3 by which it may be inflated and deflated. In order to secure the bucket 8 in any desired position within the shaft I, it is provided with a plurality of dogs I4 pivoted at its lower end I5. Attached to the outer ends of the dogs I4 are springs I6, the upper ends of which are secured to cables Il passing upwardly through tubular guard members I8 formed in the walls of the bucket. By pulling up on the cables Il, the outer ends of the dogs I4 are made to engage the walls of the drilled shaft I and any further load placed on the bucket will therefore tend to lock the bucket more securely in place. The bucket having been secured in its proper position below the uppermost bench 6, the bench holes 5 are loaded with dynamite or other exposive and then the explosive set off, thereby causing the material or ground forming the uppermost bench to fall into the bucket 8. In passing, it should be noted that the dimensions of the bucket 8 should be so correlated to the material contained in any particular layer or bench of material that the bucket is at least 0f sucient capacity to hold all of the material contained in any one bench. Preferably t'he bench holes defining any given bench are not fired simultaneously but in rotation, so that only a small quantity of rock drops into the bucket at one time. By following this procedure the shock to which the bucket is subjected is no more severe than the shock imposed on a skip when being loaded.

The bucket 8 with its contents is then raised to the surface, the contents of the bucket disposed of, and then the bucket is again lowered into the drilled shaft and secured and sealed immediately below the level of the next succeeding bench 6 so that the operation above described may be repeated. It will be seen that in this manner the drilled shaft may be progressively enlarged by successively excavating successive layers or benches, and that in accordance with my method little or no mucking is required.

While in the drawing the enlarged finished shaft has been shown as circular in cross section, my process is just as applicable to the excavation of shafts of any desired cross sectional form. All that is necessary to vary the form is to vary the length of the bench holes so as to outline or dene the desired contour.

To carry out my method successfully, care must be taken to use cables 9 and Il of sufficient strength to stand the abuse to which these members are obviously subjected. Means such as, for example, shown in Figure 5 may also be utilized to prevent excavated material from entering the space between the bucket 8 and the drilled shaft I, for otherwise such material may become wedged between these two members and prevent the bucket 8 from being raised. Also means may be provided such as shown in Figure 6 for positively holding the bucket in any desired position.

In Figure 4, concentric rings of vertical bench holes 2| have been shown. The formation of the ground being drilled will determine to a large extent whether vertical or radially extending bench holes should be used. If the lines of cleavage are vertical then it may be to greater advantage to use vertical bench holes, while if the lines of cleavage are more generally horizontal, radial bench holes as shown in Figure 1 can probably be used to better advantage. The arrangement shown in Figure 1 has the advantage that a considerable number of sets of bench holes may be simultaneously drilled by a multiple stage platform, whereas when vertical bench holes are used such as shown in Figure 4, only one series of bench holes can be drilled at any one time.

I claim:

1. The method of sinking a shaft of any given cross sectional area, comprising: drilling a substantially smooth-walled shaft of a diameter smaller than said given cross sectional area to any desired depth; progressively enlarging said drilled shaft to said given cross sectional area by blasting successive layers of the material surrounding said drilled shaft into a receptacle within said drilled shaft having an outer diameter only slightly smaller than the diameter of said shaft and located below the level of the particular layer being excavated; raising said receptacle to the surface; removing its contents; and then lowering said receptacle within said drilled shaft to a level below the level of the next succeeding layer.

2. The method of sinking a shaft of any given cross sectional area, comprising: drilling a relatively smooth-walled shaft of a diameter smaller than said given cross sectional area to any desired depth; drilling a series of bench holes extending outwardly from the drilled shaft into the material surrounding said drilled shaft to define a layer or bench of said material; loading said bench holes with an explosive; excavating said bench by exploding the said explosive and allowing the bench material to fall Within a receptacle having an outer diameter slightly smaller than the diameter of said drilled shaft and located within said drilled shaft at a level below said bench; raising said receptacle and its contents to the surface; removing said contents; and then repeating the cycle of operation until the cross sectional area of said drilled shaft has been enlarged to any desired depth.

-3. The method of sinking a shaft of any given cross sectional area, comprising: drilling a substantially smooth-Walled shaft of a diameter smaller than said given cross sectional area ton any desired depth; drilling a plurality of series of bench holes extending outwardly from the drilled shaft into the material surrounding said drilled shaft to form superposed benches of said material; progressively excavating each bench so formed by loading its bench holes with an explosive and blasting said bench into a receptacle having an outer diameter slightly smaller than the diameter of said drilled shaft and located within said drilled shaft at a level below the bench being excavated; raising said receptacle and its contents to the surface; removing the contents of said receptacle; and then positioning said receptacle within said drilled shaft below the level of the next succeeding bench.

4. The method of sinking a shaft of any given cross sectional area, comprising: drilling a substantially smooth-Walled shaft of a diameter smaller than said given cross sectional area to any desired depth; drilling bench holes into the material surrounding said drilled shaft to define a bench of said material; lowering a receptacle of a diameter slightly smaller than the diameter of said drilled shaft into said drilled shaft to a position below said bench; loading said bench holes with an explosive; excavating said bench by exploding said explosive and allowing the bench material to fall into said receptacle; raising said receptacle and its contents to the surface; removing the contents of said receptacle; and then repeating the cycle of operation until the cross sectional area of said drilled shaft has been enlarged to any desired depth.

5. The method defined in claim 4 including the steps of forming a seal between the upper edge of said receptacle and the adjacent wall of said drilled shaft prior to excavation of the bench; and the breaking of said seal prior to the raising of said receptacle to the surface.

6. The method of sinking a shaft of any given cross sectional area, comprising: boring a shaft of a diameter smaller than said given cross sectional area to any desired depth; drilling a plurality of series of bench holes extending outwardly from the bored shaft into the material surrounding said bored shaft to form. successive benches of said material; lowering a receptacle into said bored shaft to a position below the level of the uppermost bench, forming a seal between the upper end of said receptacle and said bored shaft; excavating said uppermost bench by loading its bench holes with an explosive and blasting said bench into said receptacle; breaking said seal; raising said receptacle and its contents to the surface; removing the contents of said receptacle; and then repeating the cycle of operation to successively remove said benches.

'7. The method of sinking a shaft of any given cross sectional area, comprising: drilling to any desired depth a substantially smooth-walled cylindrical shaft of a cross sectional area smaller than said given cross sectional area; excavating successive layers of material surrounding said drilled shaft into a receptacle having a diameter not substantially smaller than the diameter of said drilled shaft; supporting said receptacle by the side walls of said drilled shaft in a position below the level of the particular layer to be excavated while said layer is being excavated; raising said receptacle to the surface; and removing the contents from said receptacle.

8. The method of sinking a shaft of any cross sectional area, comprising: boring a shaft of a diameter smaller than said given cross sectional area to any desired depth; drilling bench holes into the material surrounding said bored shaft to define a bench of said material; lowering a receptacle into said bored shaft to a position below said bench; obstructing the space between the rim of said receptacle and the adjacent wall of the bored shaft to prevent wedging of material between said receptacle and said bored shaft; loading said bench holes with an explosive; discharging said explosive to blast said bench into said receptacle; removing said obstruction; and 5 raising said receptacle and its contents to the surface.

JOHN BRANNER NEWSOM.

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