The gun will be tested more thoroughly as the benches advance, Although
use is limited, the gun has an application in scaling areas where broken
rocks on the floor prohibit the use of lift machines.

CcSTS

The Bureau's experience with various types of lift trucks and boom-
mounted platforms clearly shows the economy of these machines in allowing
efficient use of scaling labor in high stopes, ‘The initial cost of such
machines is relatively high, but the saving in labor resulting from their
use outweighs the investment cost. The approximate cost of this equipment
follows:

Boom-type scaling platform... seseeeee «. $7,500
Fork lift-type scaling platform........ +. 8,500
65-foot telescoping scaling platform.......... 12,500

The units provide safe access to elevated positions and eliminate the
use of ladders or other more hazardous equipment. In addition, the mine
walls and roof can be inspected regularly and efficiently to insure safe
working areas throughout the mine.

BIBLIOGRAPHY

1. Gardner, E. Dd, and Bell, Charles H., Proposed Methods and Costs of Mining
Oil Shale, Rulison, Colo,: Bureau of Mines Inf. Circ. 7218, Nov. i9he.

2. O31-Shale Mining. Report of the Secretary of the Interior on Synthetic
Liquid Fuels Act for 1ok5. Pp, 41-he,

3. Oil-Shale Mining. Report of the Secretary of the Interior on Synthetic
Liquid Fuels Act for 1946. Pp. 68-78.

4, Gardner, E. D., Progress of Mining Studies at Bureau of Mines 0il-Shale
Mine, Anvil Points, Rifle, Colo.: A.I.M.E. Tech. Paper 2286, Min. Tech.,
Nov. 19h7,

5. Oil-Shale Mining, Report of the Secretary, of the Interior ‘on Synthetic
Liquid Fuels Act for 1947. Pp. 6-12.

6. Ertl, Tell, Wagner, John R,, Jr., and Burgh, Ernest E., The Development
of a Succeesful Hard Surfaced Bit for Drilling Oi] Shale: Bureau of
Mines Rept. of Investigations 4177, Jan, 1948,

7. Gardner, E. D., Mining Program, Bureau of Mines 0il-Shale Project, Rifle,
Colo.: Bureau of Mines Rept. of Investigations 4269, April 1948.

8. Cameron, R. J,, and Ballinger, H. J., Bureau of Mines 011-Shale Program:
National Oil Scout, and Landman's Assoc. Paper, June 1948.

9. Belser, Carl, 0il-Shale Resources of Colorado, Utah, and Wyoming: A.I.M.E.
Tech, Paper 2358, Pet. Tech., May 1948.

3932 -9








SOME INNOVATIONS IN EQUIPMENT FOR SCALING HIGH

ROOFS AND MINE WALLS
by

Brinton C. Brown, 2/ Fred D. Wright, 2/

and Homer J. Ball inger2/

CONTENTS

Summary.......e0
Introduction.....
Acknowledgments........
Existing conditions......
Outline of the problem..........
Boam-type scaling platform......
Fork lift-type scaling platform.
Sixty-five-foot sealing rig. see

Scaling bars.
Industrial gun
Costs...sseeee
Bibliography.

2
fe
pie

0 OAD WVFEWH

PoP
Foo

B

ILLUSTRATIONS

Underground lay-out of Experimental 0i1-Shale
mine.... bee e reece eee
Traveling crane w: self-leveling p.
Vertical profile of boam-type scaling rig..
Mobile blaster's platform used for scaling.
Vertical profile of fork lift-type scaling
platform.. eee eee cers ene decree ee cerevenee
Sixty-five- foot scaling rig in’ rooms 50 feet high
Vertical profile of telescopic lift machine...
Using telescopic lift scaler in rooms 27 feet
Example of versatility of the 65-foot rig; use in
the Mine yard... ssc ce rece ceccectccseveresesece
Sixty-five-foot scaler folded for traveling
through 18-foot haulagewOyS....s.esecseees eens
Lightweight scaling bars in use at the oil-shale
mine.........--- cect ence ree sensetneesseesesens
Industrial gun used for removal of loose rocks on
Mine WALLS... cece ec eee cee ner ee

W0 DIDAFWwWNNEH

Follows
page

DH KH HD WD AHF FHMND

1/ Mining engineer, U. S. Bureau of Mines, Rifle, Colo.

Report of Investigations 4739


Figure 12. - Industrial gun used for removal
of loose rocks on mine walls.


» The tower on this unit can be tilted forward about 8 degrees and tilted
back 12 degrees fram vertical by a hydravlic ctrol. The tracks are hinged
at a point 12 feet above the floor, and folding is controlled hydraulically.
With the track tilted back and the top section folded back, the traveling
height is 12 feet 6 inches,

The carriage can be overated with the track in any position. A remote-
control device wae installed between the tracks to lower the men and supplies
after the platform is raised. It consists of a fixed cable that can release
the mechanical brakes. When the engine is not running, this permits lowering
of the nlatform. Because there is no practical remote hoist control avail-
able, cone man‘mst operate the hoist from the truck cab to raise the platform.
A sectional ladder (fig. 4) was weldéd.to the side of the tracks for access
to the-raised platform.

. Over-all width of dual wheels is 96 inches, which provides enough
lateral stability to prevent falling over when tilted sideways at a 10-degree
angle. to the horizontal with a load cf 1,006 pounds on the platform in its
top position, i.é., 19 feet 6 inches above the floor.

The unit hac several advantages over the boom.type sealer:

1. The remote control brake release cnables the scalers to start
scaling at the ton of the face and work down to the floor without leaving
the platform to onerate the controls,

2, The greater length cf platform eliminates congestion and allows
the scalers to bar a greater area for each movement of ths truck,

3. Stability of the machine both laterally and axially is greater,
which eliminates seesaw motion on vneven floors,

k, Tilting the tracks forward makes it casy to work above and over
any loose rock on the flocr at the face. Also, tilting enables the men to
work with case around any irregularities that may occur in. the face and
walls without moving the truck.

There are some disadvantages of this type of machine:

1. The height of room that can be. scaled is limited, as the truck is
capable of supporting cnly a slightly higher track.

2, The front of the truck and tracks are vulnerable to falling rocks
because ,of close working conditions.

3. Chassis clearance above the floor is low, and often it is necessary
to remove scattered rock to avoid damage to the underside of the truck.

4, Loose rocks became wedged. between the dual tires.

3932 ~5-


Figure 8. - Using telescopic lift scaler Figure 9. - Example of versatility of the
In rooms 27 feet high. 65-foot rig; use in the mine
yard.


Flgure 6. - Sixty-five-foot scaling rig
In rooms 50 feet high.








Advantages of a unit of this type are:

1. There is a large saving in the capital investment when using one
machine versatile enough to operate on any level of the mine.

2, Providing an elevator at any desired place quickly and easily is
a great advantage.

3. Mounting tools, drills, etc., reduces the amount of labor required
to do odd jobs at elevated heights and results in big savings in time and
money during a period of high wages.

Some disadvantages are:

1. The front end and base of the tower are vulnerable to falling rock,
An armor plate about 8 feet high shovld be attached to the bottom of the unit
to protect the base.

2. The chassis is too low, and clearance is not alwuys enough to permit
moving the machine over rough places in the mine floor.

3. A desirable feature on this scaler would be a hoisting control on
the platform in addition to the brake release. Remote~controlled tilting
from the platform also would be advantageous.

SCALING BARS

Common practice in many metal mines is the use of solid-steel bars for
scaling. At the Sullivan mine in Canada, steel bars were replaced by alumi-
num tvbing in 1927. Present trend of the industry is to adopt magnesium and
aluminum alloy tubing for scaling bars.

Because our scalers use the bars for-an entire 8-hour shift, light
weight is of primary importance. As shown in figure 11, the design of bars
in use at the exyerimental mine is simple. ‘The steel tip is made of 1-1/8-
inch high-carbon tcol steel fabricated in our shop, as follows:

il. The shank end of the steel tip is turned and threaded on a lathe.
2. The tip is forged and then air-cooled.

3. About 2-1/2 inches of the forged tip is reheated to a temperature
just below dull-red heat and quenched. in water to harden.

The pursose of the slight bend in the tip is to provide a fulcrum near
the working end.

At the present time, handles are made from a l-inch standard 61ST alumi.
num tubing. The tubing is l-inch I.D. and has a wall thickness of 0.133 inch.
The point at which feilure occurs most frequently is the base of the threads
in the aluminum section. A possible way to overcome this trouble would be to
use a shrink fit or a resin-type cement or rivets to hold the tip in place.
Scaling bars are fabricated at an approximate cost of $3 a bar.

393; -T*




SUMMARY

This paper describes the methods and equipment developed at the Bureau's
Experimental 0il-Shale mine near Rifle, Colo., for placing men in position to
scale loose rock from the walls, pillars, and roofs of high stopes or roome.
The equipment developed at Rifle has application not only in oil-shale mining
but in most of the country's underground limestone mines and in the exploita-
tion of other mineral deposits mined in high stopes by room-and-pillar methods.
Equipment in use at Rifle includes:

1. A boom-type scaling rig with a self-leveling platform constructed on
a small “cat"-mounted crane. Men working from the platform on this machine
can efficiently scale mine walls and roofs 27 feet above the floor,

2, A conventional fork-lift truck modified to provide a remotely con-
trolled working platform from which men can scale to heights 27 feet above
the mine floor. The platform on this unit is larger than on the boom-type
rig and allows the men to inspect larger areas of the mine wall from a single
setting of the machine.

3. <A third rig, consisting essentially of a platform mounted on a tele-
scoping tower, designed and built to elevate men 65 feet above the mine floor.
Versatility of this machine permits men to work fram the platform at heights
of 5 to 65 feet. In the operating position, the unit requires a minimum
clearance of 25 feet. In the nonoperating position the tower of the machine
folds to an over-all height of 15 feet 10 inches to permit travel through
haulageways,

4, An industrial gun, lightweight scaling bars, and mechanical scalers,
which have been tried for removing loose rock from the mine walls with varying
degrees of success.

INTRODUCTION

Under the provisions of the Synthetic Liquid Fuels program, the Bureau
of Mines is cperating.an oil-shale mine near Rifle, Colo. An important
objective of the Oil.Shale Mining Division is tc devise methods and proce-
dures and develop equipment for mining oil shale on a commercial scale at
the lowest feasible cost. :

Study of the formation near Rifle indicated that a series of beds 73
feet thick presented conditions most favorable to.commercial exploitation.
A room-and-pillar variation of open-stope.mining was the method selected
with the aim to adact as many surface-mining.practices as possible to under-
ground conditions, thus increasing output per man-shift and decreasing costs.

3932 -l-




19>el

126"

i0-ES

Figure 5. - Vertical profile of fork lift-type scaling platform.


Figure |. - Lay-out of Underground Experimental mine.


65'

15'-10"

Figure 7. - Vertical profile of telescopic lift machine.



Bureau of Mines
Report of Investigations 4739

DEPART EN?

SOME INNOVATIONS IN EQUIPMENT FOR SCALING
HIGH ROOFS AND MINE WALLS

By BRINTON C. BROWN, FRED D. WRIGHT, AND HOMER J. BALLINGER

United States Department of the Interior — October 1950

| metadc38551
|




Figure 2, - Traveling crane with sel f-
leveling platform.




=

NOTE:
STANDARD 1%. THREAD,
7 TO | INCH
Peg
nm
as 4
1 :
-! e
r >
ye" “Te 2" |
Te" >|
SCALING BAR
TOOL STEEL
VARIABLE
aa he
Po —_ eee ANY NY NN
\\ whut tt We HE My
yyy ih Wibyy
WAH EA VV
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Wit VyVh
ee “WN DWANADD SD A
- TAP FOR Wy
STANDARD 17g" THREAD
7 TO 1 INCH
HANDLE
ALUMINUM ALLOY
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Figure 1. - Light-weight scaling bars in use at the

oil-shale mine.


One of the many problems confronting the engineere developing the mine
was the removal of loose rock from the roostone and mine walls at various
heights from 8 to 73 feet.

This paper describes the development of some new and unique scaling
equipment in use at the experimental mine.

ACKNOWLEDGMENTS

All members of the 0il-Shale Mining Branch contributed ideas that
aided in designing the scaling equipment. Fred D. Wright and other staff
engineers prepared the specifications for the 27-foot lift platform and
the 65-foot telescoping rig. Full credit must be given to W. H. Wagner,
president of Mixermobile Distributors, Inc., for his cooperation in detail
design and construction of both of these machines. Homer J, Ballinger,
mining engineer, worked out the details for construction of the self-
leveling platform on the boom-type scaling rig. Raymond Carlson, shop
foreman, offered suggestions for fabricating scaling bars that reduced bar
breakage by 50 percent. Lester Cargile and Charles Merrill, miners, noted
the problems while they were scaling and testing the new equipment. E, D.
Gardner, former chief of the 0i1-Shale Mining Branch, was in close contact
with the program and offered many valuable suggestions.

EXISTING CONDITIONS

Economic oil-shale beds of the Green River formation west of Rifle,
Colo., outcrop 3,000 feet above the Colorado River and lie nearly horizon-
tal, dipping less than 3 degrees to the west. The beds are not cut by
faults and have relatively few jointing planes or vertical planes of weak-
ness. Little local change in dip or strike of the beds has been noted.

The term “oil shale" is applied to a magnesium marlstone, a fine-
grained sedimentary rock containing a solid organic material know as
"kerogen," which yields shale oil upon heating. Oil shale, which occurs
both thinly laminated and massive, is a tough rock with unusual resilience.

Overlying the 73-foot measure of minable oil shale is a solid bed of
barren marlstone ranging in thickness from 6 to 8 feet. This marlstone is
the mine roofstone. It stands unsupported over spans of 60 feet or more.

The experimental mine has been developed by extending headings 60 feet
wide and 27 feet high into the 73-foot series of beds under the uncemented
pedding plane of the roofstone (fig. 1). Pillars 60 feet square, spaced 60
feet apart and staggered in one direction, support the roof. Two benches,
each 23 feet high, follow as the heading is advanced. In a three-level
operation there are working areas 27, 50, and 73 feot high. Haulage adits
entering the working areas are 18 feet high.

Blasting in underground openings loosens rocks on the walls, pillars,
and roofstone of the mine. These loose rocks present a condition that is
hazardous and a menace to the safety of men and equipment and introduces
the problem of raising men and light tools into position for removing the
loose rocks,

3932 -2-


65-FOOT SCALING RIG

As the middle bench advanced in accordance with the proposed mining
method, loose rocks om 50-foot-high pillars and walls presented a problem.
A new scaling wnit with a higher lift was required. Relative advantages of
the boam-type scaler and lift-truck scaler were considered before specifi-
cations for the new machine were prepared.

Most of the leading manufacturers of lift machines were contacted.
Mixermobile Distributors, Inc., offered to work with the Bureau on the de-
sign and construction of a unit that would operate in any room 25 to 73 feet
high. This unit (fig. 6) was called a Wagnermobile telescopic lift truck.

The telescopic lift truck (fig. 7) consists of a three-wheeled truck
22 feet 10 inches long by 11 feet wide supporting a sectional tower. Minimum
operating height of the tower is 21 feet (fig. 8). The working platform
travels along vertical tracks om the outside section of the tower fram the
lowest position (56 inches above the floor) to the maximum height of the base
section of the tower (21 feet). Upon reaching the upper limit of the base
section of the tower the platform is autamatically locked to the innermost
section of the telescoping tower. With the carriage locked on the top sec-
tion of the tower, the platform may be raised to a maximum of 65 feet (fig. 9)
by extending the other three sections of the telescoping tower. Hoisting is
accomplished through a cable and pulley arrangement, as shown in figure 7.

The truck and hoist controls are powered by a Hercules 6.cylinder Diesel
engine.

The working platform is 14 feet long by 3 feet wide ang ig enclosed with
a@ guardrail 42 inches high. The entire platform is made of steel and has an
expanded metal floor. The top front member of the guardrail is made of 3.1/2.
inch heavy-column pipe to provide a mount for percussion drilling machines.

The tower can be tilted forward 10 degrees and tilted back 5 degress
from vertical by hydraulic rams. When telescoped, the tower can be folded
back by hydraulic rams to a position horizontally over the cab of the truck.
Traveling height with the tower folded is 15 feet 10 inches (fig. 10).

Lateral stability is increased by two stabilizers 10 feet long, which
can be extended when needed. Without these outriggers, the unit has enough
lateral stability to operate on flocrs having a slope of 10 degrees with a
1-1/2-ton load at the top platform position,

A ladder is provided on each section of the tower for accessibility
when the platform is raised. As shown in figure 7, a cable and reel are
mounted on the platform guardrail. This is a remote control for releasing
the mechanical brakes. A hydraulic device operated through a sear reduction
retards the speed as the tower is lowered.

This unit has been useful for numerous jobs inside and outside of the
mine in addition to scaling. These include maintenance of electrical equip-
ment suspended from the back, elevating men for pillar research measurements,
and for a variety of tasks requiring the elevation of men and equipment to
high positions.

3932 -6-


25,

26,

27.

28.

29.

30.

31.

32.

3932

Ballinger, Homer J., Development of a Successful Multiple Percussion
Drill Carriage: Bureau of Mines Rept. of Investigations 4625, Jan, 1950.

Bureau of Mines, 1949 Annual Report of the Secretary of the Interior on
Synthetic Liquid Fuels. Part II, Oil from Oil Shale: Rept. of Investi-
gations 4652, Jan, 1950.

Sipprelle, E. M., 011-Shale Mining 1949: Colorado Mining Assoc., Denver,
Colo., 1950 Mining Yearbook, Feb. 1950, pp. 114, 116, 128.

Wright, Fred D., and Ballinger, Homer J., A Mobile Utility Station:
Mining Congress Jour., March 1950, pp. 38-39, 60.

Gardner, E. D., and Sipprelle, E. M., 0il-Shale Mining, Innovations in
Equipment, and Underground Procedures at Rifle, Colo.: The Am. Soc.
of Mech. Engr. Magazine, August 1950.

Wright, Fred D,, and Ballinger, Homer J., Development of a Successful
Mobile Compressor and Utility Station: Bureau of Mines Rept. of Inves-
tigations #709, July 1950.

Sipprelle, Emery M., and Teichman, Herbert L., Roof Studies and Mine
Structure Stress Analysis, Bureau of Mines 0il-Shale Mine, Rifle, Colo.:
A.I.M.E. Tech. Paper 2942, Mining Transactions, Feb. 1950 (now in press).

Belser, Carl, Green River 0il-Shale Reserves of Northwestern Colorado:
Bureau of Mines Rept. of Investigations (now in press).

-ll-

Interior ~ Bureau of Mines, Pittsburgh, Pa,








"Scaling," often referred to as "barring," is the removal of loose
rock from mine roofs and walls. Because each rock to be scaled presents
an individual problem, it is difficult to design a mechanical scaler;
therefore, at present scaling is done manually with lightweight bars.

Cost of scaling during periods of full production represents a sub-
stantial percentage of the direct mining cost.

The aim of scaling research is to devise more efficient means of
scaling and, if possible, to campletely mechanize the operation.

OUTLINE OF THE PROBLEM

Conventional scaling in drifts and stopes in metal mines is done at
the beginning of operations by miners and their helpers. In immediate
working areas, loose rocks in the back are removed with solid-steel bars
before drilling and/or loading machines are set up. These areas are gener-
ally small, and the height from footing to back is relatively low. Scaling
usually requires only a fraction of an hour.

In mines where open-stope methods of mining are employed, the height
of roof above the floor is often more than 90 feet. In some districts, men
employed as roof trimmers work a full 8-hour shift devoted to scaling from
100-foot ladders held in position by guy wires. The hazardous and arduous
nature of the work led to higher wages for scalers or roof trimmers.

During the period of development of the Bureau's experimental mine,
scaling was done by miners standing on truck beds and using steel-tipped
bars with aluminum handles. Men worked fram ladders to scale portions of
the mine that could not be reached from truck beds. Manual scaling, make-
shift scaling platforms, and ladders were time-consuming and inefficient.
This led to the investigation of a lift machine for rapidly placing workers
in position to scale. When thé rocms were later developed to heights of 50
and 73 feet, a thorough job of scaling was essential to insure the safety
of men and equipment, and development of such equipment was mandatory. The
remaining portion of this report is devoted to a description and discussion
of the Bureau's experience in the development of scaling equipment.

BOOM-TYFE SCALING PLATFORM

It was generally considered by the engineering staff that a platform
mounted on the end of a boam would provide the best means of elevating men
to a position for scaling, because (1) the machine controlling the boom
would be out of the way of falling rocks, and (2) it would furnish a stable
platform for the men working at various heights.

A Superior revolving crane mounted on an International TD-9 tractor was
selected (fig. 2). Working on the pantograph principle,.a self-leveling
platform and a ladder were constructed on the crane boom. The boom connects
to the tractor about 5 feet above the ground. As expanded metal platform
33 inches wide by 48 inches long, with a 42-inch-high guardrail, is pin-
connected at the end of the boom in a position that does not interfere with
the hoist cable (fig. 3). A ladder and handrail provide access to the plat-
form and act as the upper arm of the self-leveling pantograph.

3932 -3-


Figure 4. - Mobile blaster's platform
used for scaling.


SOME INNOVATIONS IN EQUIPMENT FOR SCALING
HIGH ROOFS AND MINE WALLS

By BRINTON C. BROWN, FRED D. WRIGHT, AND HOMER J. BALLINGER

* « * * « «* * «*  « Report of Investigations 4739

UNITED STATES DEPARTMENT OF THE INTERIOR
Oscar L. Chapman, Secretary
BUREAU OF MINES
James Boyd, Director

Work on manuscript completed June 1950. The Bureau of Mines will welcome reprinting
of this paper, provided the following footnote acknowledgment is made: “Reprinted from
Bureau of Mines Report of Investigations 4739.”

October 1950


lo.

il.

ie,

2B.

uy.

1b.
16.

17.

1g.

20.

al.

22,

23.

ah,

3932

Ertl, Tell, Oil-Shale Mining: A.I.M.E. Tech, Paper 2359, Min. Tech.,
July 1948,

Ertl, Tell, and Burgh, Ernest E., Observations of the Relation of
Drilling Speed to the Size of Cuttings: A.I.M.E. Tech. Paper 2409,
Min. Tech., July 1948.

Ertl, Tell, Sodium Bicarbonate from Colorado Oil Shale: Am, Mineral. ,
vol. 32, Oct. 1947, pp. 117-120.

Wright, Fred D., and Bucky, Philip B., Determination of Room and Pillar
Dimensions for the Oil-Shale Mine at Rifle, Colo.: A.I.M.E. Tech. Paper
2489, Min. Tech., Nov. 1948,

Boyd, James, Oil From Shale: Ind. and Power, vol. 55, No. 5, Nov. 1948,
pp. 78-79.

Gardner, E. D., Shale-Oil Synthetic Fuel: Engineers Bull., Nov. 1948.

Sipprelle, E. M., 0il-Shale Mining Investigations, Rifle, Colo.; The
Mines Magazine, vol, 38, No. 12, Dec. 1948, pp. 61-64.

Boyd, James, Progress in 0il-Shale Develoyment and Research: The Mines
Magazine, vol. 38, No. 12, Dec, 1948, pp. 47-50, 64.

Bureau of Mines, 1948 Annual Report of the Secretary of the Interior on
Synthetic Liquid Fuels. Part II, Oil from Oil Shale: Rept. of Investi-
gations 4457, Jan. 19k9.

Gardner, E. D., Innovations in Equipment and Underground Mining Proce-
dures at the Bureau of Mines 0il-Shale Mine, Rifle, Colo.: Colo. Mining
Assoc., Denver, Colo., 1949 Mining Yearbook, Jan. 1949, pp. 29, 31-33.

Gardner, E, D., and Sipprelle, E. M., Mechanization at the Bureau of
Mines O0il-Shale Mine: A.I.M.E. Tech. Paper 2666A, Mining Transactions,
vol. 184, Feb. 19h9.

Wright, Fred D., Mining Oil Shale at Rifle, Colo.: The Explosive Engineer,
May-June 1949, pp. 28-81, 86, 92.

Gardner, E. D., and Sipprelle, E. M., Mechanization'at the Bureau of
Mines 0il-Shale Mine: Mining Enginoer, Sept. 1949, pp. 317-323.

Gardner, E. D,, Unique Equipment Helps in Cutting Shale Mining Costs:
Engr. and Mining Jour., Nov. 1949, pp. 92-94.

Burgh, E. E., and Lankford, J. D,, Liquid Fuels from Colorado Oil Shale;
The Mines Magazine, Dec. 1949, pp. 65-73.

-10-






Future investigations will include testing verious grades and shapes
of extruded aluminum alloy tubing. One-inch-square aluminum tubing has
been used successfully in one mine for a number of years. A magnesium
alloy may lend itself to the best improvement in lightweight scaling bars
because, with greater wall thickness to give equal stiffness, there is a
greater saving in weight over aluminum tubing. In addition, the phy
properties and weldability of magnesium may be amendable, so that steel
tips can be replaced by the lighter magnesium alloy. ‘This would make an
ideal manual scaling.bar.

INDUSTRIAL GUN

A number of mines and quarries in this country have used the Remington
Industrial Gun with remarkable success in the removal of loose rock from
mine walls.

The gun, weighing 92 pounds is approximately 8-gage. It is fired by a
lanyard connected to a rotating sear, which releases a rotating hammer that
strikes the firing pin. The gun is single-shot, requiring manual opening
and closing of the mortise-tyve breech block.

Ammunition used has the appearance of an over-sized shot-gun shell.
It is loaded with a three-ounce lead projectile that develops a muzzle
velocity of more than 1,600 feet per second. Having a muzzle energy of
7,575 pounds, approximately 3-1/2 foot-tons, it delivers a powerful blow.
The manufacturer reports the energy at various distances as follows:

Foot-pounds
5,684
4 387
3,584
2,987

As shown above, et 200 yards the blow struck by the slug is approximately
1-1/2 foot-tons. Some quarries report effectiveness at 1,000 feet.

Aiming is accomplished through open sights cut in the gun cradle or by
bore sighting.

The gun in use at the cil-shale mine is mounted on a war surplus bomb
trailer, as shown in figure 12. It is easily adjusted horizontelly by means
of a hand crank (traverse gear) and vertically by means of a hand wheel, so
that it may be aimed quickly and accurately.

Tests include dislodging overhanging icicles on the cliffs, which menace
the safety of men and equipment. Large icicles were removed very successfully
at distances ranging from 50 to 200 yards. Protruding recks on pillars at
inaccessible places in rooms 50 feet high have been removed. Some rocks were
not removed. This was due in part to the elastic qualities of the rock and
shooting at points on the rocks not favoring their fractures. The cffective-
ness of the gun depends on the prowess of the operator who aims it.

3932 ~8-


Figure 10. - Sixty-five-foot scaler folded for traveling
through 1I8-foot haulageway.


7-7"

21'-10"

Figure 3. - Vertical profile of boom-type scaling rig.


The revolving boom-swing angle on this unit is 275 degrees. It is
readily seen that scalers are able to reach a wide area in the back without
moving the tractor. The crane is provided with a positive locking device
for holding the boom at any desired vertical angle both with and without
the engine in operation.

When the boom is horizontal, the clearance height is 12 feet. With
the boom fully elevated, a drill can be mounted on the pipe guardrail to
drill plug holes into the roofstone for eye pins to supvort electrical
cables, etc. Ata slightly lower platform position, the roofstone can be
inspected thoroughly by the miners, and loose rock can be removed when
necessary.

Several advantages of the boom-type scaling platform are:

1. It enables men to work above obstacles on the floor.

2, There is no damage to the equipment due to falling scaled rock.
3. Men are moved to any desired position easily and rapidly.

kh, The machine may be used as a portable crane without interference
from the platform.

5. It is very handy for mounting percussion drills cr stover machines
for drilling plug holes into the roofstone and ribs.

Some disadvantages of the machine which led to the development of a new
type of scaling platform are:

1. A remote-control device on the platform to maneuver the boom up
and down and laterally was impractical to incorporate in this type of machine.

2. The tractor must be moved to and from the face as the boom travels
in an arc when moved up and down.

3. On uneven flcors, the weight of the men on the end of the boom some-
times causes the machine to tilt - in effect, a seesaw motion - even though
the boom is designed to carry 1 ton at all platform heights.

FORK LIFT-TYFE SCALING PLATFORM

A special piece of equimment was designed and constructed primarily
for charging blast holes, sume of which are 25 feet above the flocr of the
mine (fig. 4). This unit is also used as a scaling platform. No similar
equipment designed specifically for this purpose is in use elsewhere, to
the authors' knowledge.

This unit is a modified Wagnermobile Duo-Way lift machine adapted to
elevate men and explosives to various heights above the mine floor. It con-
sists of a three-wheeled fork-lift truck with 23-foot vertical tracks (fig. 5).
A 5- by 10-foot wooden platform encircled by a 42-inch guardrail is mounted on
the fork tines of the truck, ‘The truck is powered by a Diesel engine.

3932 -4e