Mitchell Portable Belt Conveyor

1. The Mitchell portable belt conveyor is designed for handling loose materials, such as small coal and stone, sand, and gravel. The headroom enables it to be passed through low doorways, under gantries, etc., without the danger of fouling overhead wires or other obstructions and it may be used from loading points within the holds of barges, through the doors of railway wagons, in excavators, etc.

2. The main framework, on which the belt is carried, consists of a fixed boom assembly to which a cantilever boom is attached by hinge connection.  The power unit, reduction gearing, and driving and tension drums, are mounted in the fixed frame; the hinged boom assembly is raised by a hydraulic luffing jack which is attached to both frame units.  It is possible to mount the main frame as a whole in four alternative positions relative to the axle, by means of the axle frame provided.  By selection of axle position, and adjustment of the cantilever boom, it is possible to vary the discharge height and belt angle to suit particular conditions, as shown in the diagrams below

3. The belt is of the troughed type, 18 in, wide, and runs at a speed of approximately 200 ft. per minute.  Spring-loaded tension gear is fitted, and the belt is cleaned by scraper gear at the discharge end and on the tension drum.  The supporting idlers on the troughed side of the belt are of the 3-pulley type, and the return idlers of the single-pulley type.

4. A Petter air-cooled gasoline engine, Type PAl, is fitted.  The reduction gearing comprises two chain roller drives, and the drive may be disengaged by a hand-operated chain type clutch.

5. Pneumatic-tyred road wheels are fitted, and the wheels are mounted on swivelling axles which enable the machine to be man-handled to serve different discharge points.  A towing attachment is fitted at the boot of the conveyor.

6. As a guide to capacity, the machine will handle small coal at 40/50 tons per hour, and stone or sand weighing 1 cwt. per cu. ft. at 60/80 tons per hour, depending upon the facilities available for loading.  Up to five men can load at one time.  If desired, one machine can load on to another in sequence.

The machine is provided with an adjustable axle frame allowing the conveyor to be used in any four of the positions described and illustrated in the drawing.

This item of equipment was transferred to Part 7 from Part 8 by AL20.  This entry has been updated to AL51.

Conveyor       

• Type - Rubberised canvas belt

• Width - 18 in.

• Length - 50 ft. (pulley centres), 51 ft. 3 in. (total    length)

• Shaft bearings - 1-3/8 in. phosphor bronze

• Troughing roll assemblies - 3-pulley type, 4 in. dia. with ball bearings

• Return roll assemblies - Single pulley type, 4 in. dia. with ball bearings

• Driving drum - 20 in. x 13½ in., steel tube type, phosphor bronze bearings.

• Tension drum - 20 in. x 10½ in., steel tube type, phosphor bronze bearings

Reduction gearing       

• First reduction drive - Chain 5/8 in. pitch simple chain; 102 links with 21-tooth pinion

• Second reduction drive - Chain ¾ in. pitch simple chain; 118 links

• Countershaft driver sprocket - 457 teeth

• Countershaft driven sprocket - 19 teeth

• Driving drum sprocket - 95 teeth 

Clutch

• Make and Type - Renold chain clutch, No. 641013

Running gear

• Wheels - Two, size 3.62 x 19 in.

• Tyres - Pneumatic, 6-19, 6 ply rating

• Wheel bearings - Roller

• Towing attachment - Mild steel bracket with 1¼ in. dia. hole, fitted to lower portion of drum boot

Belt speed  - 200 ft. per mm. (app rox.)

Capacity - Varies according to feed, angle of operation and type of material.  Examples: - small coal, 40/50 tons per hr.; stone or sand weighing 1 cwt. per cu. ft., 60/80 tons per hr.

Operating angles and discharge heights - Can be varied by selection of alternative axle positions and adjustment of the cantilever boom (see accompanying diagrams)

Maximum towing speed 9 m.p.h.

Dimensions - see diagram above.

Baxter granulator, 16 in x 5 in/ Baxter stone crushing and screening plant, 12 tons per hour (mobile)

The Baxter 16 in. x 5 in. granulator is a mobile crushing machine for granulating pieces of stone into small chips (nominal size ¾ in. cube) used in road building. The size of the mouth of the machine jaws is 16 in. x 5 in.  The crushing machine is driven by a Ruston, Type 3VSO diesel engine; engine and crushing machine, complete with belt drives, controls, and screen are mounted on a four-wheeled trolley complete with towing bar.

MT vehicle require for transportation -

• SMT, 20 ton, 16 wheel, low-loading trailer or similar

This item of equipment appears to have been added to the 2nd Edition by the issue of AL12.

Granulator operating speed - 300 rpm

Weight - 11 tons.

Overall Dimensions -

• Length - 27 ft. 2 in.

• Width - 6 ft. 9 in.

• Height - 9 ft 6 in

• Wheelbase - 9 ft 9 in

• Ground Clearance - 6 in

• Turning radius - 10 ft

Iowa crushing plant, 25/40 tons per hour, Model 1524

1. The plant is used to produce crushed rock and is designed to operate with the Iowa screening plant, 25/40 t.p.h., Model 2416, to produce either crushed rock and gravel to re-surface roads or aggregate for preparing bituminous surfaces and concrete work.  It is designed for power loading but can be fed by trucks or bulldozers from a ramp or quarry wall.

2. The crusher is trailer-mounted with air-controlled brakes on all wheels and hand-controlled parking brakes on the rear wheels. A removable dolly allows the plant to be handled as either a semi or a six-wheeled trailer.

3. The crusher consists of a feed (or charging) hopper, a reciprocating feeder, a jaw crusher, and a delivery conveyor. Power is supplied by a gasoline engine. Raw material fed into the feed hopper passes to the reciprocating feeder which conveys the material to the jaw crusher, by-passing undersized material direct to the delivery conveyor belt. Crushed material from the jaw crusher is also deposited upon the delivery conveyor belt.

MT vehicle require for towing -

• AEC, Matador, 4x4, Tractor

This item of equipment appears to have been added to the 2nd Edition by the issue of AL26.

Raw material size - 13 in. x 22 in. maximum.

Finished material size - Adjustable from 1 in. to 2½ in. maximum

Output -

• Aggregate passing an opening of 1 in. - 12 to 20 tons per hour

• Aggregate passing an opening of 1½ in. - 15 to 27 tons per hour

• Aggregate passing an opening of 2½ in. - 24 to 40 tons per hour

Trailer Frame

• Type - Gooseneck

• Jack - Screw type, 2 in. x 12 in., 20 tons capacity, ratchet head

Running gear

• Front - Dolly type: Spencer Trailer Co., Model No. J.D.309 Special: weight 3,685 lb.

• Rear - Tandem wheel oscillating beam with rigid main axle

• Wheels - Budd Wheel Co., No. 45520-6¾ in. dish

• Brakes - 17¼ in. x 5 in. Spencer heavy duty 'S' cam

• Brake controls - Bendix-Westinghouse air control to front and rear with hand control to rear only

• Tyres - Nine 12.00 x 20. Four mounted in pairs on the front; four mounted singly on the rear; one spare

Feeder

• Type - Reciprocating plate

• Width (plate) - 20½ in.

• Hopper size - 5 ft. 6 in. square opening

• Hopper capacity - Level: 1½ cu. yds. Heaped: 2 cu. yds

• Clutch - Twin disc. Plant serial numbers 5653-5662 and 5682-5701 use Model BFT-206. Plant serial numbers 6286-6343 use Model CL-208, No. XA5748

Crusher

• Type - Overhead eccentric jaw

• Size - 15 in. x 24 in.

• Drive - V-belts from engine

• Speed - 250 rpm

• Bearings - SKF self-aligning roller

Delivery Conveyor

• Type - Belt

• Width - 18 in

• Length (pulley centres)  - 18 ft.

• Driver and idler shaft bearings - Self-aligning sealed ball

• Troughing roll assemblies - Three-roll type, 4½ in. diameter, with pre-lubricated sealed ball bearings

• Return roll assemblies - Single-roll type,4½ in. diameter, with pre-lubricated sealed ball bearings

• Drive pulley - 10 in. x 18 in. steel (split) lagged

• Idler pulley - 8 in. x 18 in. steel (split)

• Belt length - 38 ft. 6 in. total

Weight - 32,070 lb

Overall Dimensions -

• Length (Semi-trailer) - 25 ft. 9½ in.

• Length (six-wheeled trailer) - 32 ft 6 in (with dolly draw-bar resting on ground)

• Width - 8 ft. 8 in.

• Height - 10 ft 6 in

• Wheelbase - 17 ft 7½ in

• Track, front dolly - 70½ in

• Track, rear - 62¾ in

• Turning radius - 20 ft

• Minimum road clearance - 9 in

Iowa screening plant, 25/40 tons per hour, Model 2416

1. The plant is used to produce screened rock and sand and is designed to operate with the Iowa crushing plant, 25/40 t.p.h., Model 1524, to produce either screened material to re-surface roads or sized aggregate for preparing bituminous surfaces and concrete work.

2. The plant is trailer-mounted with air-controlled brakes on all wheels and hand-controlled parking brakes on the rear wheels.  A removable dolly allows the plant to be handled as either a semi or a six-wheeled trailer.

3. The screener consists of a feed conveyor, a vibrating screen, a screen hopper, a double roll crusher, a return system consisting of a roll conveyor and an elevating wheel, two side delivery conveyors (one for graded material and one for sand or undersized material), and a gasoline engine.  Material fed to the feed hopper passes to the feed conveyor and on to a vibrating screen box containing two screens, one above the other. The upper sizing screen receives all material from the feed conveyor. Material passing through the sizing screen falls on to the second screen; material which does not pass the sizing screen passes to a roll crusher, is crushed and carried by the roll conveyor to an elevating wheel which lifts it back to the feed conveyor to be re-circulated through the screen.

4. Material falling on to the second screen is either passed through to the sand hopper or passes on to the graded material hopper.  Delivery conveyor belts on each side of the plant remove the contents of the sand hopper and the graded material hopper.

MT vehicle require for towing -

• AEC, Matador, 4x4, Tractor

This item of equipment appears to have been added to the 2nd Edition by the issue of AL26.

Raw material size - 3½ in maximum.

Finished material size - Adjustable from ¼ in. to 2½ in. maximum

Output -

• Aggregate passing an opening of ¼ in. - 15 tons per hour

• Aggregate passing an opening of ½ in. - 30 tons per hour

• Aggregate passing an opening of ¾ in. - 40 tons per hour

• Aggregate passing an opening of 1 in. - 55 tons per hour

• Aggregate passing an opening of 1½ in. - 85 tons per hour

• Aggregate passing an opening of 2½ in. - 140 tons per hour

Trailer Frame

• Type - Gooseneck

• Jack - Screw type, 2 in. x 12 in., 20 tons capacity, ratchet head

Running gear

• Front - Dolly type: Spencer Trailer Co., Model No. J.D.309 Special: weight 3,685 lb.

• Rear - Tandem wheel oscillating beam with rigid main axle

• Wheels - Budd Wheel Co., No. 45520-6¾ in. dish

• Brakes - 17¼ in. x 5 in. Spencer heavy duty 'S' cam

• Brake controls - Bendix-Westinghouse air control to front and rear with hand control to rear only

• Tyres - Nine 12.00 x 20. Four mounted in pairs on the front; four mounted singly on the rear; one spare

Feed Conveyor

• Type - Belt

• Width - 18 in

• Length (pulley centres)  - 20 ft 7 in

• Driver and idler shaft bearings - Self-aligning sealed ball

• Troughing roll assemblies - Three-roll type, 4½ in. diameter, with pre-lubricated sealed ball bearings

• Return roll assemblies - Single-roll type,4½ in. diameter, with pre-lubricated sealed ball bearings

• Drive pulley - 10 in. x 18 in. steel (split) lagged

• Idler pulley - 8 in. x 18 in. steel (split)

• Belt length - 44 ft

Vibrating Screen

• Type - Cedarapids horizontal

• Width - 3 ft.

• Length - 8 ft.

• No of decks - 1½

• Top deck - No 3 size: One 3 ft. x 5 ft. with ¾  in. square openings and two with 1¼-in square openings, No 3 size: One 3 ft. x 3 ft. with ¾  in. square openings and two with 1¼-in square openings.

• Bottom deck - No 3 size: 3 ft. x 4 ft. with 3/16 in. square openings.

• Drive - Three Gates Model 144C V-belts from main plant countershaft

• Speed - 875 rpm

• Bearings - SKF self-aligning roller

Delivery Conveyor

• Type - Belt-folding style with hand-elevating winch

• Width - 18 in

• Length (pulley centres)  - 14 ft.

• Driver and idler shaft bearings - Self-aligning sealed ball

• Troughing roll assemblies - Three-roll type, 4½ in. diameter, with pre-lubricated sealed ball bearings

• Return roll assemblies - Single-roll type,4½ in. diameter, with pre-lubricated sealed ball bearings

• Drive pulley - 12 in. x 18 in. steel (split) lagged

• Idler pulley - 8 in. x 18 in. steel (split)

• Clutch - Twin disc.  Plant serial numbers 5653-5662 and 5682-5701 use Model BFT-206, No X-8115.  Plant serial      numbers 6286-6343 use Model CL-208, No XA5748

• Belt length - 29 ft. 8 in. total

Sand Conveyor

• Particulars as for the Delivery Conveyor, above

Crusher

• Type - Double Roll

• Size - 24 in. x 16 in.

• Drive - V-belts from main plant countershaft to roll crusher countershaft.

• Speed - 67 rpm  420 ft/min

• Main Bearings - Timken tapered roller

• Countershaft Bearings - SKF self-aligning roller

Roll Conveyor

• Type - Belt

• Width - 18 in

• Length (pulley centres)  - 7 ft. 11 in

• Driver and idler shaft bearings - Self-aligning sealed ball

• Troughing roll assemblies - Three-roll type, 4½ in. diameter, with pre-lubricated sealed ball bearings

• Return roll assemblies - Single-roll type,4½ in. diameter, with pre-lubricated sealed ball bearings

• Drive pulley - 10 in. x 18 in. steel (split) lagged

• Idler pulley - 8 in. x 18 in. steel (split)

• Belt length - 17 ft. 1 in. total

Elevating Wheel

• Type - Drum, trunnion mounted

• Diameter - 67 in. inside

• Width - 18 in. inside

• Drive - Trunnion, by cut tooth sprockets and finished roller chain

• Speed  (trunnions)- 75 rpm

• Speed  (elevating wheel)-13½ rpm  242 ft/min

• No of adjustable plates - 18

• Trunnion Bearings - Self-aligning sealed ball

Weight - 35,150 lb

Overall Dimensions -

• Length (Semi-trailer) - 29 ft. 8½ in.

• Length (six-wheeled trailer) - 36 ft 5 in (with dolly draw-bar resting on ground)

• Width - 8 ft. 0 in.

• Height - 10 ft 6 in

• Wheelbase - 19 ft 0½ in

• Track, front dolly - 70½ in

• Track, rear - 67-7/8 in

• Turning radius - 20 ft

• Minimum road clearance - 13½ in

Goodwin Barsby, 10 tons per hour, crushing and screening plant, Cornwall unit.

1. This crushing and screening plant is portable, and is belt-driven by a separate Blackstone C.I. engine. The plant comprises, basically, an Acme crusher, an elevator, a rotary screen in three sections with an outer jacket, and three storage hoppers, all of which are mounted on one frame; the primary drive is by belt to the crusher, and the secondary drive is by belt from the crusher to the screen drive, which incorporates also a chain drive to the elevator.

2. The crusher is fed manually, and the aggregate is transferred, by the elevator, to the screens for grading, whence it falls into the appropriate storage hopper. Aggregate which is rejected by the screens, passes from the end, down a shute, to the crusher for further treatment.

3. When the engine is in position, it should be secured to prevent movement during operation; sleepers or baulks of timber are normally used as wedges for this purpose.

MT vehicle require for towing -

• Plant transporter

This item of equipment appears to have been added to the 2nd Edition by the issue of AL26.

Working load speed of engine - Max 800 rpm

Speed of crusher - Max 250-275 rpm

Running gear - 4 x cast iron wheels, 2 ft. 6 in. dia. x 7 in. face

Crusher - Acme, 16 in. x 10 in., with reversible manganese jaws and renewable side-plates.  Bearings are in white metal and are lubricated through Stauffer grease cups.

Screens - Rotary; section perforations, 1¾ in., 7/8 in., and 7/8 in. with outer jacket perforations of ¼ in.

Crusher drive - Belt, 6 in. x 44 ft. approx. (at 19 ft, centres) x 5-ply

Elevator drive - Primary - belt, 15 ft. 6 in. x 4 in. x 4-ply, rubber impregnated.  Final - chain, 27 ft. 6 in.

Elevator drive pulleys - Driver, 9 teeth; driven, 24 teeth

Elevator chain sprockets - Upper, 14 teeth; lower, 9 teeth

Elevator chain - 186 links, with a K 2 attachment

Elevator bucket - 47 x size, 10 in.

Controls - Manual

Weight (in working order) -

• Plant (less engine) - 22,400 lb

• Engine - 3,138 lb

• Engine (less two flywheels) - 2,130 lb

Overall Dimensions (in working order)-

• Length (Plant) - 21 ft. 0 in.

• Length (Plant with engine) - 36 ft 6 in (approx)

• Width - 7 ft. 10 in.

• Height - 17 ft 3 in

• Depth, below ground level of elevator - 16 in

• Track - 6 ft 7 in

Iowa crushing and screening plant, 10 tons per hour, Model VE

1. The plant is used to crush and screen aggregate. It supplies four sizes of screened material plus oversized material which is too large to pass the widest screen.

2. The plant consists of an adjustable roll crusher which feeds crushed material into a cylindrical rotating screen having three sizes of perforation. Material rejected by the largest screen passes through the cylinder and falls to the ground at the end of the plant; material passing either of the two largest screens falls into separate heaps beneath the plant; material passing the smallest of the three rotating screens is re-screened into two sizes by a fourth smaller-mesh screen and also falls beneath the plant.

3. The plant is portable and is mounted on a chassis with four steel-tyred wheels. The crusher and screens are powered by a diesel engine.

MT vehicle require for towing -

• Plant transporter

This item of equipment appears to have been added to the 2nd Edition by the issue of AL37.

Chassis

• Type - Straight, short wheel base

• Axle, front - Universal type with king pin

• Axle, rear - Rigid beam type

• Wheels, front - 24 in. x 6 in. steel-tyred, spoked

• Wheels, rear - 30 in. x 8 in. steel-tyred, spoked

• Wheel bearings - Cage type industrial roller

• Spindle size - 2½ in. diameter

• Pull tongue length - 63 in. from centre of towing eye to hinge

• Wheel base - 93¾ in.

• Front track - 50¼ in.

• Rear track - 71¼ in.

Crusher 

• Type - One corrugated and one smooth roller

• Size - 16 in. x 16 in. rollers

• Drive - Flat belt from engine

• Roll shafts - 5 in. dia.

• Countershaft - 2-1/16 in. dia.

• Drive pulley - 36 in. dia. x 10 in. wide

• Speed of rolls - 105 to 113 rpm

• Speed of countershaft - 180 to 195 rpm

• Main frame - 6 in. H-beams

• Weight - 4,500 lb. (crusher only)

Screen Sizes - ¾, ½, ¼ and 1/8 in.

Finished material sizes

• Over ¾ in
• Under ¾ in and over ½ in
• Under ½ in and over ¼ in
• Under ¼ in and over 1/8 in
• under 1/8 in

Weight (in working order) -

• Plant (less engine) - 22,400 lb

• Engine - 3,138 lb

• Engine (less two flywheels) - 2,130 lb

Overall Dimensions -

• Length - 23 ft. 8½ in. (without draw-bar)

• Width - 6 ft. 11 in.

• Height - 8 ft 7¼ in

Goodwin Barsby, screen and high discharge hopper

1. The screen and high discharge hopper is a portable unit and is used to form part of a crushing and screening plant.  It is powered by an Austin 8 hp gasoline engine, and comprises a rotary screen in three sections with a wire outer jacket, and three storage hoppers; the lower longitudinal members of the frame are detachable.

2. Aggregate is fed, by conveyor, from one or more crushers to the screens for grading, whence it falls into the appropriate storage hopper; rejected aggregate passes from the end of the screen for further treatment by a crusher or granulator.      

MT vehicle require for towing -

• not stated

This item of equipment appears to have been added to the 2nd Edition by the issue of AL40.

Running gear - 4 x cast iron wheels, 2 ft. 6 in. dia. x 7 in. face

Screen power unit - Austin 8 hp gasoline engine (see above)

Screen drive  -

• Primary - 4 x 21/32 in. V-ropes to intershaft

• Secondary - Intershaft, through clutch and spur pinions, to countershaft

• Final - Countershaft, through crown and bevel pinions to screen shaft

Pulleys -

• Driver, 5.25 in. pitch circle dia.

• Driven, 13 in. pitch circle dia.

Clutch -  Croft, No. 8 DFS disc (min. torque 103 tons/ft. at 345 rpm)

Spur. pinions -

• Driver, 16 teeth x 4 in. diametral pitch x 2¾ in. face

• Driven, 120 teeth x 4 in. diametral pitch x 2¾ in. face

Bevel   pinions ...         ...         ...        

• Driver, 13 teeth x l½ in. diametral pitch

• Driven 84 teeth x l½, in diametral pitch

Finished material sizes - ¼ in, 1¼ in and 3/16 in

Overall Dimensions -

• Length - 18 ft. 9½ in. (with draw-bar raised)

• Width - 8 ft. 3 in.

• Height - 17 ft 4½ in

• Wheelbase - 11 ft 3½ in

• Track - 6 ft 11 in

• Ground Clearance (frame) - 1 ft 10 in

• Ground Clearance (hopper outlets) - 5 ft 9 in

Pegson stone crushing and screening plant, 10/12 tons per hour (mobile)

1. The Pegson mobile stone crushing and screening plant is a self-contained unit mounted on a four-wheeled trailer chassis which is fitted with pneumatic tyred wheels, a centrally pivoted front axle with a towbar and two-line air brakes operating on the rear wheels.

2. Power for the crusher is provided by a water-cooled diesel engine which is mounted at the front of the chassis, and the drive is transmitted by a flat belt from the engine to the crusher; the rotary screen is driven by a flat belt from the crusher.

3. The machine is fed manually from a loading platform, and the screen plates, fitted to the rotary screen, separate the crushed material into four sizes.  Three hinged stabilising jacks, fitted to the rear of the chassis, are lowered to support the chassis and provide additional stability when operating the plant; two of the jacks can be detached from the rear and fitted towards the front of the chassis for lifting the front end of the equipment.

4. The plant is suitable for towing at speeds up to 20 mph. and is provided with electric convoy lighting, reflectors, and trailer plates; the towing vehicle must be fitted with a two line pressure air system.  A mechanical parking brake is coupled to the brakes and is operated by a handwheel fitted to the side of the chassis.

MT vehicle require for towing -

• 10 ton tipper, or other suitable vehicle with trailer brakes

This item of equipment appears to have been added to the 2nd Edition by the issue of AL76.

Make and Model - Pegson 12 TPH Jaw crusher and screen, No AX 122

Type - Single toggle 20 in x 9 in         

Crusher

Flywheel speed - 280 rpm        

Size of mouth - 20 in x 9 in

Feeding size of material - 8 in max     

Capacity - 12 tons per hour        

Screen            

Speed of rotation - 16 rpm           

Gauge of plate or mesh/Size of hole

• 13 SWG (Mesh)/ 3/8 in

• 3/16 in (Plate)/ ¾ in

• 3/16 (Plate)/ 1½ in

• 3/16 (Plate)/ 2¼ in

Dimensions                

Length of screen - 5 ft 0 in (effective length)   

Diameter of screen - 2 ft 3 in

Height of loading platform - 5 ft 3½ in

Length of biding platform - 9 ft 4 in

Width of loading platform - 4 ft 0 in

Ground clearance of screen - 1 ft 9 in (at lowest point)

Dimensions

• Overall length

  • With tow-bar horizontal - 22 ft. 0 in.

  • With tow-bar raised - 20 ft. 6 in

  • With tow-bar removed (or turned towards the rear) - 20 ft. 0 in

• Overall width - 6 ft. 6 in.

• Overall height - 8 ft. 11 in

• Wheelbase - 14 ft. 6 in.

• Track,

  • rear wheels - 5 ft. 6 in

  • front wheels - 4 ft. 0 in

• Turning circle (dia.) - 20 ft. 6 in

• Tow-bar pivot height - 1 ft. 10 in

• Minimum ground clearance - 1 ft. 5 in

Weights

• Total weight (in working order) - 8 ton 15¼ cwt

• Rear axle loading - 6 ton 8¼ cwt

• Front axle loading - 2 ton 7 cwt

Goodwin Barsby, crushing plant, 25/40 TPH, Model 'Goliath' (Primary plant)

1. The crushing plant is the primary unit of a two-piece mobile crushing and screening plant, and can be used as an independent unit or as part of a composite plant, in conjunction with the granulating and screening plant, described below, which forms the secondary unit.

2. The crushing equipment is trailer-mounted on a pneumatic-tyred, six-wheeled chassis, fitted with two-line air operated hydraulic brakes which are applied from the towing vehicle; hydraulically operated parking brakes are provided which are applied by turning a handwheel, situated at the rear of the trailer.  Six hinged jacks are fitted to the chassis for supporting the plant in the operating condition.

3. Road lighting equipment to conform to the Road Traffic Regulations is fitted to the trailer, and the system is supplied from the towing vehicle lighting system by means of a jumper cable.  The engine platform is hinged, so that the width can be reduced for travelling; the delivery conveyor and access ladders can be stowed and lifting tackle is provided for erecting the delivery conveyor or preparing it for travelling.

4. A feeder hopper situated at the rear of the trailer is of sufficient capacity to enable the machine to be loaded by a 5/8 cu. yd. excavator, or loading shovel.  A feeder conveyor collects the material from the hopper and delivers it to the breaker mouth; a grill is fitted at the discharge end of the feeder conveyor to allow small material to by-pass the crusher.  Crushed material, together with any small material that has by-passed the crusher, is collected by a delivery conveyor which discharges the material at a suitable height for direct feeding into the hopper of the secondary unit, or into trucks when the primary unit is used independently.

5. Power for the crusher is supplied by a diesel engine, mounted at the front of the trailer; the drive is transmitted through a clutch and V-belts. A generator is also driven by V-belts from the engine, to supply a 100 volt, DC lighting system which is provided to enable the plant to be used at night; four lamp standards are fitted to the plant and lamps, leads, sockets and plugs are provided with the plant equipment.

Stores Ref - 89E/18

MT vehicle require for towing -

• 10 ton 6 x4, load carrying truck equipped with two-line air pressure braking system

This item of equipment appears to have been added to the 2nd Edition by the issue of AL91.

Make and Model - Goodwin Barsby 25/40 TPH. Model 'Goliath' (Primary unit)

Feeder

• Type - Apron plate

• Width - 24 in

• Length - 8 ft. 3 in.

• Hopper size - 8 ft. 0 in. long x 6 ft. 0 in. (7 ft. 6 in. wide, with extension plates)

• Hopper capacity - 4 cu. yds. (5 Cu. yd. with extension plates)

Crusher

• Type - Goodwin 'Acme' single toggle

• Size  - 24 in. x 15 in

• Jaws - Reversible type

Delivery conveyor      

• Type - Belt

• Width - 24 in

• Length - 25 ft. 0 in.

Lighting equipment    

• Generator - GEC 'Witton' 0.5 kW., 100 volt, DC

• Lamps - Four 60 watt hand-lamps with 6 ft. 6 in. leads.  Fitted lamp standards

Lilting tackle  

• Type - Yale, Pul-lift

• Capacity - 30 cwt.

Stabilizing jacks - Six, 6 ton, screw type (attached to chassis)

Plant in working condition

Dimensions

• Overall length - 37 ft. 6 in.

• Overall width - 9 ft. 0 in

• Overall height (lamp standards erected) - 16 ft. 6 in

• Delivery conveyor discharge height - 8 ft. 3 in

• Feed hopper loading height - 10 ft. 0 in.

Crusher

Flywheel speed - 320 rpm.

Size of mouth - 24 in. x 15 in

Feeding size of material - Maximum 15 in. (on longer axis)

Maximum jaw setting 5 in. (primary unit operating independently)

Minimum jaw setting  2½ in

Normal jaw setting (for use with secondary unit) - 31 in

Size of crushed material - 3 in. to 5 in. approx.

Dimensions (Plant in travelling condition)

• Overall length (draw-bar horizontal) - 32 ft. 8 in.

• Height - 12 ft. 11 in

• Width - 8 ft. 3 in

• Ground clearance (under rear axle) - 1 ft. 5 in

• Wheelbase - 16 ft. 0 in.

• Track  

  • Rear wheels -  6 ft. 6 in

  • Front wheels  - 5 ft. 5 in

• Turning circle (diameter) - 38 ft. 0 in

Weights          

• Total weight - 21 ton, 15 cwt

• Front axle loading - 7 ton 5 cwt

• Rear axle loading - 14 ton, 10 cwt.

Goodwin Barsby, crushing plant, 25/40 TPH, Model 'Goliath' (Secondary plant)

1. The granulating and screening plant is the secondary unit of a two-piece mobile crushing and screening plant, and can be used as an independent unit or as part of a composite plant in conjunction with the crushing plant, or primary unit, described above.

2. The equipment is mounted on a pneumatic tyred, six-wheeled, trailer chassis, fitted with two-line air operated hydraulic brakes which are applied from the towing vehicle; hydraulically operated parking brakes are provided, which are applied by turning a handwheel situated at the rear of the trailer.  Road lighting equipment is fitted to the trailer, and the system is supplied from the towing vehicle by means of a jumper cable.

3. The plant consists of the following units: -

   1. Feed hopper and main feed conveyor

   2. Three-deck vibrating screen

   3. Granulator

   4. Fine crushing rolls

   5. Return crushed stone conveyor

   6. Raff wheel elevator

   7. End delivery conveyor

   8. Left-hand wing conveyor

   9. Right-hand Wing conveyor.

4. Partially crushed material is fed into the small feed hopper of the main feed conveyor, either from the primary unit delivery conveyor or from direct loading when the secondary unit is used independently, and is conveyed by the main feed conveyor to the three-deck screen.  Material that is too large to pass through the top deck is passed to the granulator for further crushing, and material from the centre deck can be passed to the fine crushing rolls, where it is reduced to fines, or the rolls can be by-passed and the material can be fed from the centre deck to the right-hand wing conveyor as coarse grade.

5. From the granulator and fine crushing rolls the crushed material is conveyed to the Raff wheel elevator and returned to the feed conveyor to be conveyed to the top deck of the screens for grading.  Material rejected from the centre deck is graded as coarse and is discharged by the right-hand delivery conveyor, material passing through the centre deck but too large to pass through the bottom deck is discharged as medium grade by the left-hand wing conveyor, and the material which passes through the bottom deck is discharged by the end conveyor as fine grade.

6. Power for operating the units is supplied by a diesel engine and is transmitted through belts, gears and shafts to the various units; clutches are incorporated in the conveyor drives.  The diesel engine also drives a generator to supply current to a lighting system to enable the plant to be used at night; nine lamp standards are fitted to the plant, and lamps, leads, sockets and plugs are provided with the plant equipment.

Stores Ref - 89E/19

MT vehicle require for towing -

• 10 ton 6 x4, load carrying truck equipped with two-line air pressure braking system

This item of equipment appears to have been added to the 2nd Edition by the issue of AL91.

Make and Model - Goodwin Barsby 25/40 TPH, Model 'Goliath' (Secondary unit)

Main conveyor

• Type - Belt

• Width - 4 in.

• Length (between pulley centres) - 31 ft. 3 in

Screen

• Type - Goodwin 'Vitex', vibrating three-deck

• Width - 3 ft. 0 in.

• Length  - 10 ft. 0 in.

Granulator

• Type - Goodwin 'Acme' single toggle

• Size - 30 in. x 5 in.

• Jaws - Reversible type

Crushing rolls

• Type - Double roll, fine crushing

• Size - 24 in. dia. x 14 in. face

Crushed stone conveyor

• Type - Belt

• Width - 20 in. (5080 cm.)

• Length (between pulley centres) - 17 ft. 9 in

Raff wheel elevator

• Type - Revolving drum

• Size - 6 ft. 0 in. dia. x 1 ft. 6 in

• Lifters - Renewable steel plate

Wing delivery conveyors (2) (left-hand and right-hand)

• Type - Belt

• Width - 18 in. (4572 cm.)

• Length (between pulley centres) - 18 ft. 3 in.

End delivery conveyor

• Type - Belt

• Width - 20 in. (5080 cm.)

• Length (between pulley centres) - 16 ft. 9 in. (51054 cm.)

Lighting equipment

• Generator - GEC 'Witton', 0.9 kW. 100 volt DC.

• Lamps - Nine 60 watt hand-lamps with 6 ft. 6 in. leads. Fitted lamp standards

Lifting tackle

• Type - Yale, Pul-lift

• Capacity - 30 cwt.

Stabilizing jacks - Six. 6 ton, screw type (attached to chassis)

Dimensions (machine in working condition)

• Overall length (end conveyor unfolded) - 42 ft. 0 in.

• Height (without lamp standards), Main conveyor head raised - 13 ft. 7 in

• Width (wing conveyors unfolded) - 38 ft. 9 in.

• Loading height (feed hopper) - 7 ft. 6 in

• Discharge height of wing conveyors - 8 ft. 3 in.

• Discharge height of end conveyor - 9 ft. 0 in.

• Size of material for feeding into granulator - 3½- in

Granulator

• Speed - 323 rpm.

• Discharge jaw setting for product of minus 1½. in. - I¼ in. approx

• Minimum discharge setting - ¾ in

• Reduction ratio in size of crushed material - 6 to 1 (approx.)

• Approximate analysis of crushed material produced with jaw discharge setting of l¼ in. -

  • Less than 3/8 in - 16.35%

  • ¾ to 3/8 in - 13.75 %

  • 1½ to ¾ in - 69.9%

Crushing rolls

• Countershaft speed - 113 rpm.

• Rolls speed - 75 rpm.

• Maximum size of material fed to rolls - 1½  in cube

• Reduction ratio in size of crushed material - 3 to 1 (max.)

• Approximate screening analysis of material to ¾ in. and less

  • Less than 3/16 in - 15%

  • 3/8 to 3/16 in - 20%

  •  5/8 to 3/8 in - 30 %

  • ¾ to 5/8 in - 35%

Capacity of plant

• Primary and Secondary units working as a composite plant

  • Rolls by-passed (3 sizes)

    • 1½ in and less - 30/35 tons per hour

    • ¾ in and less - 15/17 tons per hour

  • Granulator and rolls (2 sizes)

    • ¾ in and less - 20/25 tons per hour

• Secondary unit working independently

  • Rolls by-passed (3 sizes)

    • 1½ in and less - 80/100 tons per hour

  • Granulator and rolls (2 sizes)

    • ¾ in and less - 60/70 tons per hour

Dimensions (Plant in travelling condition)

• Overall length (draw-bar horizontal) - 40 ft. 9 in

• Overall height (main conveyor head lowered) - 13 ft. 0 in.

• Overall width (wing conveyors folded) - 9 ft. 0 in.

• Wheelbase - 21 ft. 0 in

• Track, front wheels - 5 ft. 6 in

• Track. rear wheels  - 7 ft. 9 in

• Ground clearance (under rear axle) - 1 ft. 6 in.

• Turning circle (dia.) - 40 ft. 0 in

Weights          

• Total weight - 31 ton, 8 cwt

• Front axle loading - 8 ton 7 cwt

• Rear axle loading - 23 ton, 1 cwt.

Pegson Granulating and Screening plant, 5/6 tons per hour (mobile)

1. The Pegson mobile granulating and screening plant is an adaptation of the same basic machine as that used for the crushing and screening plant which is described fully in Section 1, above..

2. The basic machine is a dual purpose machine which can be adapted to operate either as a crusher or a granulator by fitting suitable jaws and rotary screens.

3. The data given below applies only to the machine when it has been adapted for use as a granulator; all other data which applies to both granulating and crushing plants is given in the entry shown in Section 1.

MT vehicle require for towing -

• 10 ton tipper, or other suitable vehicle with trailer brakes

This item of equipment appears to have been added to the 2nd Edition by the issue of AL76.

Make and Model - Pegson 6 TPH Granulator and screen, No AX 122

Type - Single toggle 20 in x 5 in         

Granulator

Flywheel speed - 280 rpm        

Size of mouth - 20 in x 5 in

Feeding size of material - 4 in max     

Capacity - 6 tons per hour        

Screen            

Speed of rotation - 16 rpm           

Gauge of plate or mesh/Size of hole

• 13 SWG (Mesh)/ 1/8 in

• 3/16 in (Plate)/ ¼ in

• 3/16 (Plate)/ ½ in

• 3/16 (Plate)/ ¾ in

Dimensions                

Length of screen - 5 ft 0 in (effective length)   

Diameter of screen - 2 ft 3 in

Height of loading platform - 5 ft 3½ in

Length of biding platform - 9 ft 4 in

Width of loading platform - 4 ft 0 in

Ground clearance of screen - 1 ft 9 in (at lowest point)

Dimensions

• Overall length

  • With tow-bar horizontal - 22 ft. 0 in.

  • With tow-bar raised - 20 ft. 6 in

  • With tow-bar removed (or turned towards the rear) - 20 ft. 0 in

• Overall width - 6 ft. 6 in.

• Overall height - 8 ft. 11 in

• Wheelbase - 14 ft. 6 in.

• Track,

  • rear wheels - 5 ft. 6 in

  • front wheels - 4 ft. 0 in

• Turning circle (dia.) - 20 ft. 6 in

• Tow-bar pivot height - 1 ft. 10 in

• Minimum ground clearance - 1 ft. 5 in

Weights

• Total weight (in working order) - 8 ton 15¼ cwt

• Rear axle loading - 6 ton 8¼ cwt

• Front axle loading - 2 ton 7 cwt

Bucyrus-Erie blast hole drill, 6 in, Type 27-T

1. The plant consists of a power unit installed in a girder frame, which also carries a number of reels and a telescopic derrick.  The complete unit is mounted on chain driven tracks which can be controlled independently for steering.

2. The machine is designed for deep well boring or blast-hole drilling as appropriate, and is powered by a Caterpillar diesel engine, Type D3400.

MT vehicle require for transportation -

• SMT, 20 ton, 16 wheel, low-loading trailer or similar

This item of equipment appears to have been added to the 2nd Edition by the issue of AL23.

• Capacity (drilling side) - 140 ft of ¾ in line
• Capacity (storage side) - 180 ft of ¾ in line or 230 ft of 5/8 in line
• Line pull - 5,200 lb
• Line speed - 155 ft per min at 1,300 rpm engine speed

Sand reel:

• Capacity - 450 ft of 3/8 in line
• Line pull - 1,200 lb
• Line speed - 385 ft per min at 1,300 rpm engine speed

Bumper reel:

• Capacity - 450 ft of 3/8 in line

By the operation of the gear change lever, one forward and reverse are obtainable and the speed over the ground in either gear is 0.9 mph at full engine revolutions.

Depth of bore - Normally 100ft, absolute maximum - 300 ft

Size of bit - 6 in or 6-5/8 in

Running gear -

• Width between track centres - 8 ft 7 in

• Length of track - 11 ft 8½ in

• Shoe width - 1 ft 2 in (oversize)

• Shoe width - 10 in (standard)

Weight - 19,000 lb

Overall Dimensions -

• Length - 15 ft. 9 in.

• Width - 6 ft. 6 in.

• Height (derrick raised) - 43 ft 0 in

• Height (derrick raised) - 9 ft 9 in

Bucyrus-Erie bit dresser, Model 8

1. Used in conjunction with a suitable furnace, this machine is capable of mechanically dressing worn bits of from 4 in. to 7 in. dia. by from 2 ft. to 6 ft. in length.  It is belt driven and can be powered either by a suitable electric motor or by one of several Le Roi gasoline engines.  The ram hammer operates like a piston and is carried in adjustable side channels.

2. The machine comprises, basically, two parallel "I" section steel girders upon which are mounted the serrated racks for adjustment of the bit saddle, the ring die holder, and the ram driving mechanism.  This latter consists of two stiff cantilever spring packs mounted on a common crank bearing, and having at their extremities swinging links to which the ram itself is attached. A single-throw crankshaft, driven via a slipping clutch contained within the belt pulley, carries the bearing and supplies the action. It is carried in two plain bearings.

3. Control of the ram action is effected through the slipping clutch, to which the main operating lever is connected.

4. The bits are held in place against the inner splines of the saddle by a sliding clamp, which is foot-operated through the cranked, flat-section bar in front of the machine.  The clamp is carried on a slide bar, running the length of the serrated rack at the back of the machine,

This item of equipment appears to have been added to the 2nd Edition by the issue of AL51.

Overall Dimensions

• Basic Machine

  • Length - 14 ft. 1¼ in.

  • Width - 2 ft. 10 in.

  • Height (to flywheel rim) - 1 ft 8 in

• Machine with Le Roi XP3 engine (as illustrated above)

  • Length - 14 ft. 1¼ in.

  • Width - 4 ft. 8 in.

  • Height (to flywheel rim) - 4 ft 2½ in

Weight

• Machine (nett) - 3,000 lb

• Machine with Le Roi XP3 (nett) - 700 lb

Climax jackhammer rock drill, RV 258 Mk 2

1. The Climax jackhammer is a medium weight pneumatic rock drill of the dry type designed for the perforation of rock or similar material by a combined percussive and rotary action.

2. This particular drill can either be used as a hand drill or can be mounted on the Climax Wagonette drill mount (see below) and used as a wagon-mounted drill.

3. The air supply must be sufficient to maintain a pressure of 75 lb. per sq. in. at a maximum consumption of 80 cu. ft. of free air per minute.

Stores Ref - 89E/87

This item of equipment appears to have been added to the 2nd Edition by the issue of AL88 and was amended in AL95.

Makers' designation - Hand hammer dull Type RV 258 Mk 2 (dry)

Control - Plug type cock; three position    

Rod retainer - Spring retaining latch

Air adapter - ¾ in. BSP parallel, male

Oil reservoir - In front cover; lubrication of valve mechanism by air line lubrication fitted to the air hose adjacent to tool 

Bore - 2-5/8 in   

Stroke - 2¼ in

Rate of rotation - 1 in 31    

Air consumption - 96cu  ft of free air per minute at 80 lb per sq in pressure   

Recommended air pressure - 80 lb. per sq. in.    

Drill rod shank size - Hexagonal, 4¼ x 1 in

Dimension and weight        

Overall length (less drill rod) - 22½ in

Weight (less drill rod) - 52½ lb

Climax Wagonette drill mount

1. The Climax Wagonette drill mount consists basically of a tubular frame, provided with wheels and jack-legs, on which a jackhammer or a drifter-type rock drill can be mounted so that the combination of drill and mount form a wagon drill assembly.

2. The drill, usually a Climax jackhammer drill Type RV 258 Mk. 2 (see above) is mounted to a shoe free to slide in a swivel-mounted cradle attached to the top of the frame.  A four-cylinder air motor attached to the rear end of the cradle is connected to the shoe through a reduction gearbox and a feed screw so that operation of the air motor moves the shoe, and the drill along the cradle, thus providing an automatic feed to the drill.

3. The frame and the cradle are capable of adjustment so that vertical, horizontal, or angular drilling, can be effected from flat, sloping, or uneven ground.

4. All controls for the drill and the feed motor, with the exception of the exhaust valve blowing device of the drill, are located on a control valve assembly mounted on the underside of the cradle.

Stores Ref - 89E/87

This item of equipment appears to have been added to the 2nd Edition by the issue of AL89.

.Makers' designation - Wagonette Type WLD -M 1/1 Mk. I with pneumatic feed, cradle assembly piston-motor (4 ft. steel change

Recommended air pressure - 80 lb. per sq. in

Air consumption - Average: 96 cu, ft. of free air per mm. for drill; 30 cu. ft. of free air per min. for feed motor; both at 80 lb per sq. in.

Feed speed - 8 ft. per min. (max.)

Withdrawal speed - 9 ft. per min

Tyres - Dunlop Industrial 4.00 x 8, 6-ply

Dimensions and weights

• Overall length of cradle - 6 ft. 0 in.

• Width across wheels - 4 ft. 2 in

• Weight, with drill - 4 cwt. approx.

Climax jackhammer rock drill, RV 237/1

1. The Climax jackhammer rock drill, Type 237/1 is a light rock drill of the dry type fitted with an exhaust valve blowing device.  It is suitable for drilling holes of up to 2 in terminal diameter to a depth of 10 to 12 ft. in medium or hard rock.

2. Perforation of the rock is effected by a combined percussive and rotary action, rotation of'the drill rod being effected during the up-stroke of the piston by a conventional rifle bar and nut assembly.

Stores Ref - 89E/86

This item of equipment appears to have been added to the 2nd Edition by the issue of AL88.

Makers' designation - Type RV 237/1 (dry)

Control - Plug type cock; three position    

Rod retainer - Spring retaining latch

Air adapter - ¾ in. BSP parallel, male

Oil reservoir - At base of cylinder; lubrication of valve and rotation mechanism by air-line lubricator fitted to the air hose         adjacent to the tool

Bore - 2-1/8 in   

Stroke - 1¾ in

Air consumption - 65cu  ft of free air per minute at 80 lb per sq in pressure   

Recommended air pressure - 80 lb. per sq. in.    

Drill rod shank size - Hexagonal, 3¼ in. by 7/8  in.

Overall length - 1 ft. 9 in

Weight (less drill rod) - 33 lb

Ingersoll-Rand, jackhammer, Model JB-4

1. The Ingersoll-Rand jackhammer, Model J B-4, is a light rock drill of the dry type fitted with an exhaust valve blowing device, it is suitable for drilling holes of up to 2 in. terminal diameter to a depth of 10 to 12 ft. in medium or hard rock.

2. Perforation of the rock is effected by a combined percussive and rotary action, rotation of the drill rod being effected during the upstroke of the piston by a conventional rifle bar and nut assembly.

Stores Ref - 89E/81

This item of equipment appears to have been added to the 2nd Edition by the issue of AL95.

Makers' designation - Model JB-4, 45 lb. class

Control - Plug type cock; three position    

Rod retainer - Foot-operated retaining latch

Air adapter - ¾ in. ASP parallel, male

Oil reservoir - At base of cylinder; lubrication of valve and rotation mechanism by air-line lubricator fitted to the air hose         adjacent to the tool

Drill rod shank size - Hexagonal, 4¼ in. by 1 in.

Recommended air pressure - 70 - 90 lb. per sq. in.    

Weight (less drill rod) - 45 lb

Holman 'Silver Bullet' jackhammer, Models No 2 & 4

No photograph of this item is available at present

1. The Holman 'Silver Bullet' jackhammers, Models No. 2 and No. 4 are light rock drills provided with throttle-controlled blowing. No. 2 is a dry drill equipped to take 3¼ in. by 7/8 in. hexagonal shanked drill rods; No. 4 is a wet drill equipped to take 4¼ in. by 1 in. drill rods.  Apart from this, the two models are identical.

2. Perforation of the rock is effected by a combined percussive and rotary action, rotation of the drill rod being effected during the upstroke of the piston by a conventional rifle bar and nut assembly.

3. Both models of the jackhammer ate suitable for drilling holes of up to 2 in. terminal diameter to a depth of 10 or 12 ft. in medium or hard rock.

Stores Ref - 89E/84

This item of equipment appears to have been added to the 2nd Edition by the issue of AL95.

Makers' designation - Silver Bullet Handrill, No 2 and No 4

Control - Plug-type air inlet valve; three-position     

Rod retainer - Spring retaining latch

Air adapter - ¾ in. BSP parallel, male

Water adapter (No. 4 only) - ½ in. B.S.P. male

Oil reservoir - Not provided, external air-line lubricator must be used.

Drill rod shank size

• No 2 - Hexagonal, 3¼ in. by 7/8 in.

• No 4 - Hexagonal, 4¼ in. by 1 in.

Recommended air pressure - 70 - 90 lb. per sq. in.    

Weight

• No 2 - 58 lb

• No 4 - 62 lb

Bore - 2-5/8 in

Stroke - 2½ in

Overall length - 24 in

Ingersoll-Rand, jackhammer, Model JB-5

No photograph of this item is available at present

1. The Ingersoll-Rand jackhammer, Model JB-5, is a light rock drill of the dry type fitted with an exhaust valve blowing device.  It is suitable for drilling holes of up to 2 in. terminal diameter to a depth of 10 to 12 ft. in medium or hard rock.

2. Perforation of the rock is effected by a combined percussive and rotary action, rotation of the drill rod being effected during the upstroke of the piston by a conventional rifle bar and nut assembly.

Stores Ref - 89E/82

This item of equipment appears to have been added to the 2nd Edition by the issue of AL95.

Makers' designation - Model JB-5, 55 lb class

Control - Plug-type cock; three-position

Rod retainer - Foot-operated retaining latch

Air adapter - ¾ in. ASP parallel, male

Oil reservoir - At base of cylinder; lubrication of valve and rotation mechanism by air-line lubricator fitted to the air hose adjacent to the tool

Drill rod shank size - Hexagonal, 4¼ in. by 1 in.

Recommended air pressure - 70 - 90 lb. per sq. in.    

Weight (less drill rod) - 55 lb approx

Ingersoll-Rand, jackhammer, Model JA-55

No photograph of this item is available at present

The Ingersoll-Rand jackhammer, Model JA-55, is a light rock drill of the dry type fitted with an exhaust valve blowing device. It is suitable for drilling holes of up to 2 in. terminal diameter to a depth of 10 to 12ft. in medium or hard rock.

Perforation of the rock is effected by a combined percussion and rotary action, rotation of the drill rod being effected during the upstroke of the piston by a conventional rifle bar and nut assembly.

Stores Ref - 89E/80

This item of equipment appears to have been added to the 2nd Edition by the issue of AL95.

Makers' designation - Model JA-55, 55 lb. class

Control - Plug-type cock; three-position

Rod retainer - Foot-operated retaining latch

Air adapter - ¾ in. ASP parallel, male

Oil reservoir - At base of cylinder; lubrication of valve and rotation mechanism by air-line lubricator fitted to the air hose adjacent to the tool

Drill rod shank size - Hexagonal, 4¼ in. by 1 in.

Recommended air pressure - 70 - 90 lb. per sq. in.    

Weight (less drill rod) - 55 lb approx

Holman Rotogrind Model 40 TC

1. The Holman Rotogrind, Model 40TC, is a heavy duty, air-operated, portable grinding machine The machine is capable, normally, of a wide variety of uses but the particular machines supplied to the Service have been fitted with green grit (silicon carbide) grinding wheels and have been provided with bench brackets so that they can be converted into bench-type grinding machines.

2. The optimum speed of a green grit wheel is rather less than other types of wheel and, because of this, the machines in the Service are fitted with a non-standard governor assembly.  No attempt must be made to fit any other type of wheel to the machine except 8 in, nominal dia, green grit wheels.

3. The machine is only, to be used for the resharpening and regauging of carbide-tipped rock drill bits.  Inexperienced operators should use the machine as a bench-type grinder and move the drill rod in relation to the machine; after experience has been gained, quicker results will be obtained by holding the drill rod in a vice and moving the grinder in relation to the bit.

Stores Ref - 89E/25

This item of equipment appears to have been added to the 2nd Edition by the issue of AL89.

Makers' designation - Radial Rotogrind, Size 40 TC

Wheel size - 8 in. nominal dia. by 1 in. width

Hole diameter - 5/8 in

Free governed speed - 3,100 rpm.

Air adapter - ½ in. BSP.

Recommended air pressure - 80 lb. per sq. in.

Air consumption - 45 cu. ft. of free air per min. at 80 lb. per sq. in. pressure

Overall length - 21½ in.

Weight, less bench bracket  - 20 lb.