US2216989A

US2216989A - Taking mine samples

Info

Publication number: US2216989A
Application number: US201044A
Authority: US
Inventors: Clair Matilda Elliott St
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-02-18
Filing date: 1938-04-09
Publication date: 1940-10-08
Anticipated expiration: 1957-10-08

Description

Oct. 8, 1940. M. E. s1. CLAIR TAKING MINE SAMPLES Filed April 9, 195a Patented Oct. 85 1940 TAKING MINE ISAMPLES Matilda Elliott St. Clair, Johannesburg, Union of South Africa I Application April 9, 1938, Serial No. 201,044 In the Union of South Africa February 18, 1938 3 Claims. (o1.2s2 19) The present invention relates to methods of and apparatus for taking mine samples, especially samples of hard rock formations. samples arecommonly taken by cutting grooves across theexposed face of the formation at a number of placesalong the face of the formation and collecting the. material cut out of each of the grooves. The grooves are cut by manual operation with a hammerand chisel which is not'only laborious, especially in the case of hard rock formations, but tends to inaccuracyowing to the difficulty of. making each and every groove even in depth and width. An important factor in this respect is that a chisel is not well adapted for simultaneously cutting out material from the body of the groove and cutting the sides of the groove by means of the extremities of its cutting edge.

One object of the invention is to effect the cutting of the grooves in a more accurate manner. Another object of the invention is to out the edges of the grooves in a less laborious manner. Other objects and advantages of the invention will appear from the following description when taken in conjunction with the accompanying drawing comprising Figures I to V.

Figure I is an elevation of a rock sawing masawing mechanism in half section.

Figure II is a side elevation of the machine of Figure I.

Figure III shows a pair of saw cuts made in a rock face by the machine of. Figures I and II.

Figure IV illustrates a method of wedging out rock from between two saw cuts made by. the machine of Figures I and II. l

chine according tothe invention, showing the Figure V illustrates the use of a moil for chip-.

ping out rock between the saw cuts of Figure III or IV.

The rocksawing machine of Figures I and II has a casing 2 housing a compressed air motor, an electric motor or other power motor. The casing 2 is provided with two handles 3 and 4 for holding it against the rock face. The motor in the casing 2 drives a shaft 5 onto the free end of which is screwed a nut 6 whichclamps a rock sawing wheel and depth gaugeassembly between itself and a collar 1. The sawing and gauge assembly comprises a distance piece 8, two cheeks it, one on each side of a rock sawing wheel M,

an exchangeable spacing collar 2 which determines the distance between the cuts of each pair of saw cuts, and two further cheeks l3, l4, one on each side of a second sawing wheel l5; the cheeks 9, Ill, l3, I4, the collar l2 and the saw- ,the key It. Such ing wheels l5 being all keyed to the shaft by A depth gauge in the form of a harderubber tyred wheel I! is mounted on the spacing collar |2 between the sawing wheels H,

|5 by means of a ball race I8 which is protected by means of felt-lined washers I9 and 28 respectively. The sawing wheels l5 have widened rims 2|, 22 made of material capable of sawing hard rock, preferably material containing diamond grit. w

The rims 2|, 22 of the sawing wheels l5 are partly enclosed by means of a semi-circular guard 23 which extends about half way round the length of the rims 2|, 22 of the sawing wheels l5 and is supported from the casing 2 by means of a bracket 24 clamped onto a collar 25 screwed l onto a bush 26 projecting from the casing 2. The guard 23 is made hollow and is provided with water jets 21 and a water inlet 28 to enable streams of cooling water to be sprayed onto the 2 rims 2|, 22 of the wheels when they are in use; these streams of water also have a lubricating action on the rims 2|, 22.

In order to use the machine for taking mine samples, the length. of the spacing collar I2 is so chosen that the two sawing wheels I5 are at a distance apart which is equal to the width chosen for the samples and the radius of the depth gauge wheel I! is so chosen that it is less the radius of each of the sawing wheels 30 5 by an amount which is equal to the depth chosen for the samples. In practice the width chosen for the samples may be about /2 to v1 inches and the depth about to 1 inch. The motor is then switched on and the rims 2|, 22 of the rotating sawing wheels l5 are pressed against the face of the rock at the place where a sample is to be taken, and the machine is traversed across the exposed face of the formation so as to make two parallel saw cuts, as indicated by the

cuts

29 and 30 in Figure III, which are shown cut across a vein of ore 3|. The wheels l5 are allowed to cut into the rock to a depth determined'by the rim of the guide wheel coming into contact with the rock face.

The sample isolated by the

saw cuts

29, 30 may then be removed e. g. by chipping with a moil or hand chisel 34 (Figure V), the rock chippings 35 being collected in a pan 36. 1

It is preferable, however, to employ a Wedge chisel and wedge it into one of the saw cuts as this causes the rock to flake off in large cakes. The use of a wedge chisel in this manner is illustrated by the wedge chisel 31 (Figure IV) inl serted into the saw cut 3|]. When employing a wedge chisel it is advantageous to make other cuts 38 transverse to the

edge cuts

29, 30, so that the wedge chisel will wedge off the cakes of rock more easily; these pairs of transverse cuts may e. g. be 6 inches apart when employing a wedge chisel having a width of 3 inches. After the main body of the rock has been removed from the groove, the bottom of the groove may be smoothed off by the use of a moil as illustrated in Figure V.

In addition to the increased speed and ease of operation, the invention has the advantage that it permits of greater accuracy in getting a true sample of the ore because the long edges of the sample are readily cut in straight lines across the face of the rock, and because the distance between the two saw cuts is accurately fixed for each sample. In addition, the depth of the whole body of the sample is determined by the depth of the saw cuts which is maintained approximately the same for each sample by means of the depth gauge ll. Moreover, the total bull: of rock taken from each sampling position may be made much less than in the case of hand cutting to give an equally representative sample and all the rock from each sampling position may constitute a single sample instead of constituting several samples as in the current practice of hand operation.

It is possible to use a sawing machine which has only one sawing wheel but is otherwise similar in construction to that already described; in this case care has to be taken in guiding the machine to keep the second cut of each pair parallel to the first.

I claim:

1. A machine for making saw cuts through the exposed face of a body of rock, comprising a power driven shaft, two diamond impregnated sawing wheels rigidly mounted on said shaft, and a depth gauge rotatably mounted on said shaft between said sawing wheels.

2. A machine for making saw cuts through the exposed face of a body of rock, comprisin a power driven shaft, two rock sawing wheels rigidly mounted on the shaft, and a depth gauge rotatably mounted on said shaft between said sawing wheels.

mounted on said shaft between said sawing wheels.

MATILDA ELLIOTT ST. CLAIR.