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CLOSE THIS BOOKSpecial Public Works Programmes - SPWP - Stone Paving-Blocks - Quarrying, Cutting and Dressing (ILO - UNDP, 1992, 60 p.)
3. HANDLING THE BLOCKS
VIEW THE DOCUMENTHandling and transporting stone blocks
VIEW THE DOCUMENTTools
VIEW THE DOCUMENTBlock-handling techniques

Special Public Works Programmes - SPWP - Stone Paving-Blocks - Quarrying, Cutting and Dressing (ILO - UNDP, 1992, 60 p.)

3. HANDLING THE BLOCKS

Handling and transporting stone blocks

Before secondary cutting, the large stone blocks should be transported to the site where the paving-blocks will be dressed. The operations of handling and transporting are together known as stone haulage. In many quarries, the know-how of the stone-haulier has been replaced by mechanised techniques. However, where tractors, cranes, elevators, lorries, etc. are not available, or where such mechanised methods prove too costly or poorly adapted to local conditions, the techniques of the stone-haulier are called upon.

The stone-haulier's tools are simple and can often be manufactured locally.

Tools

· a pinch-bar, or failing this, a quarry bar (crowbar);

· some hardwood rollers, both cylindrical and convex to make it easy to change the direction of a load;

· a rack and pinion jack, capable of lifting or moving heavy loads;

· a hand-cart: a sturdy two-wheeled trolley, made from large-section metal tubing, capable of moving blocks weighing several hundred kilos. It is pulled by one or more workers depending on the load and terrain (see pages 28 and 29).


Pinch-bar

Diameter: approx. 37 mm
Length: approx 1800 mm


Cylindrical roller


Convex roller

Approximate dimensions:

Diameter: 50- 100 mm
Length: 1000 mm


Jack

Safety:

The wearing of steel-capped safety shoes provides effective protection for feet, which are particularly exposed to accidents during stone-handling. Leather work gloves should also be worn.

Block-handling techniques

In order to lift a block of stone with a pinch-bar, a chock (a quarry-stone or square wooden block) is placed under the bar which is used as a lever.


Figure

The greater the ratio between A and B, the easier it is to raise the block.


Easy to lift


Difficult to lift

Lifting a 200 kg block with the chock placed as in diagram (2) requires twice as much force as lifting the 200 kg block with the chock placed as in diagram (1).


Figure

Should a block need to be tipped over onto another side, this is achieved by sliding chocks under the block as soon as it is raised so as to be able to turn it over easily. It is possible to up-end a block, either by placing increasingly bigger chocks under it with the help of a pinch-bar or by using a jack.

Safety:

Never stack chocks on top of each other, except in a box, or they may slip and cause injury to the worker. Clean up the work environment: never let tools, chocks or other small objects lie around on the ground.

Before a block tips over, position a chock so that the block does not fall flat on the ground but balances on the chock. The chock serves as a pivot, making it easy to rotate or change the direction of the block.


Figure

If the stone to be moved is not too heavy and it is possible to hold it upright, it can be pivoted first on one corner then the other. This is called "walking" the stone.


Figure

Blocks weighing up to several hundred kilos can be moved using a two-wheeled trolley or hand cart. The techniques described above can be used to load the block onto the hand cart.


Loading a block onto a hand cart

Safety:


How to lift a load correctly

The correct way to lift a load: with the feet well apart and the back straight, bend at the knees. Lift the load, keeping it as close to the body as possible, gradually straightening the legs. Never lift a load in the way depicted on the left. Excessive strain is placed on the back muscles and spine.


Transporting a block on a hand cart.

To move a large block over smooth hard ground, use can be made of rollers directly on the ground or on a "railway" constructed of planks to smooth out any irregularities of the terrain.

The block moves along on two rollers; when one roller comes out behind the block it is moved to the front and so on.


Figure


Figure

To change direction, the rollers are placed perpendicular to the required path.


Figure

When changing direction, use of convex (and not cylindrical) rollers improves manoeuvrability.


Transporting a block using a tractor and metal cable

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