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INDEX

I. Definitions of various cutting schemes I.1. Continuous Borings I.2. End Hole Boring I.3. Vertical Through Cut I.4. Vertical Cut With Flam-Jet Pre-arrangement I.5. Vertical Step Cut I.6. Horizontal Cut

II. Preparing The Holes II.1. Marking And Making Horizontal Holes II.2. Marking And Making Vertical Holes II.3. Remaking of Holes

III. Positioning Machines and Equipment III.1. Positioning Flywheels III.1.1. High Fore Flywheel III.1.2. High Rear Flywheel III.1.3. Lower Front Flywheel III.2. Positioning of Rails III.3. Placing the Machine on the Rails III.4. Lining Up of Main Flywheel III.4.1. Calculation of Gradient III.4.2. Calculation of Flywheel Axle Position

IV. Mounting the Diamond Wire IV.1. Cleaning the Work Area above the Bank IV.2. Calculating the Length of the Wire to be Used IV.3. Checking the Wear of the Wire IV.4. Inserting the Wire in the Holes IV.5. Pre-loading the Wire IV.6. Joining the Wire IV.7. Placing the Wire on the Main and Small Flywheels IV.8. Pre-arrangement of the Cooling System

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V. Starting the Cut V.1. Slight Pre-Tension of Wire V.2. Running the Wire Through by Hand V.3. Checking the Rotation of the Wire V.4. Starting the Machine in "Manual" Position V.5. Rounding Corners V.6. Intermediate Pauses during the Cutting V.7. Moving and Removing the Rear Flywheel V.8. Changing the Positions of the Water Jets

VI. Continuous cutt ing VI.1. Switching to Automatic Operation VI.2. Periodical Checking and Replacement of Joint VI.3. Checking and Repositioning the Cooling System VI.4. Checking the Wear of the Wire and the Advancement of the Cut VI.5. Inserting Boring Bars into the Cut

VII. Exit ing the Cut VII.1. Replacing the Wire VII.2. Starting the Final Cutting Phase VII.3. Exiting the Cut 13 VII.4. Recovering and Storing Wires Used and Equipment

VIII. Turning Over and Cutting Up the Bank VIII.1. Detaching the Bank VIII.2. Moving the Bank Away with a Hydro-Bag VIII.3. Turning Over the Bank with Hydraulic Jacks VIII.4. Sectionalising into Blocks

IX. Diagnosis and Solution to Problems §

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I. Definitions of various cutting schemes

I.1. Continuous Borings

The traditional method for separating the bank is as follows: A series of parallel holes (24 - 32 mm in diameter) are made at approximately 15 cm from one another, along the separation surface (FIGURE 1). At this stage the holes are loaded with appropriate amounts of explosive and blasted with a detonating fuse. Water can be used depending on the rock sensitivity and the form or dimensions of the bank.

The advantages and disadvantages of this method follow:

Advantages:

- Speed - Simplicity

- Low initial cost

Disadvantages

- Danger - Noise, especially during the explosion - Irregular shape of blocks subsequently sectionalised

NOTE: The irregular shape is to be considered as damage as the purchaser only buys the inner parallelepiped volume of the block by measuring its sides with respect to the narrowest points (FIGURE 2). On top of this, the transport and storage costs are relative to the gross weight of the block, including the portion not being paid for due to its irregular shape.

- Evident or hidden damages to the material extracted and to that adjacent - Low quarry yield

NOTE:

Low yield is not only relative to the percentage of saleable material from that extracted, but also to that of scrap management costs (handling, storage and problematic and environmental rules).

The diamond wire has made a big contribution in resolving all these problems, and is ever more present in granite quarries throughout the world. Nowadays, thanks to the diamond wire, it is possible to substantially improve the overall yield of extraction in granite quarries.

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Nevertheless, the continuous borings method is today still the most widespread. Diamond wire cutting is integrated into various granite quarry operations with an intensity that depends on the stoping technique used.

I.2. End Hole Boring

To use a diamond wire, it is necessary to make holes along the cutting perimeter of the rock so as to allow the wire to enter. The holes are made wider than those used in the continuous boring method for convenience. These are usually 87 mm in diameter. The end hole boring machine is made up of a powerful pneumatic hammer that runs along a guide to allow the tool (a end hole hammer) to enter the rock. This machine can bore in any direction, from horizontally to vertically (FIGURE 3). It is important to use excellent quality tools that are well sharpened (these can be sharpened with the appropriate equipment). Sometimes when blunt tools are used, the rate of advancement of the rods declines while the push required for penetration increases. If this happens, the hole is irregularly deviated. During boring, it must be born in mind that the rock can tend to slightly deviate the hole in a certain direction (this is usually common throughout the quarry). This can be compensated for by bearing in a counteracting direction.

I.3. Vertical Through Cut

The vertical through cut is the simplest case in which the diamond wire can be used. It is sufficient to make a through hole at the cutting base so as to close the diamond wire circuit (FIGURE 4).

I.4. Vertical Cut With Flam-Jet Pre-arrangement

In some cases, in granite quarries, a Flam-jet is used to open the main cutting fronts. The Flam-jet is a heat lance that uses an oil and compressed air mixture combustion. During the ignition phase, oxygen and acetylene are used. The Flam-jet makes cuttings 80-120 mm wide and is capable of a speed of 1 -1.5 rrWh. The heat jet is moved backwards and forwards along the cut by hand, gradually destroying the granite (FIGURE 5A-5B).

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The advantages and disadvantages of this method follow:

Advantages: - Reduced size and weight - Flexible usage (it can make cuttings in uncomfortable positions and in limited spaces).

Disadvantages: - Higher cost than diamond wire - Alteration in granite near to surface (about 10 cm per side). - Extremely noisy - Intense pollution - Prevention of doing different jobs in a wide surrounding area .

The Flam-jet can be used as a support tool to the diamond wire for quarry stoping. It is especially useful for making main cuttings from which diamond wire cuttings are then made. In this case, it is sufficient to make a horizontal hole for each wire cutting, thanks to the channel cut with the Flam-jet (FIGURE 6).

I.5. Vertical Step Cut

If possible, it is best to avoid using the Flam-jet because of its disadvantages by stoping the quarry with steps: 30 cm steps are cut in succession with a diamond wire (It is essential to calculate the step between two consecutive cuts so as to have enough space to install the boring machine for the horizontal and vertical holes). This way the extracted banks are perfectly cut on four sides. Make two holes for each cut, one horizontally and one vertically (two corner cuts can use a single vertical hole)-(FIGURE 7).

I.6. Horizontal Cut

The diamond wire can also be used for horizontal cuts which completes its list of applications regarding the extraction of banks. Use the holes meant for the corresponding vertical cuts (FIGURE 8).

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II. Preparing The Holes

II.1. Marking And Making Horizontal Holes VERT (Vertical cut)

Mark the cutting line on the upper plane of the bank, starting from the vertical hole position up to the front corner, parallel with the external face. The distance must be equal to (or a multiple of) the size of the greater side of the block. Use a plumb line to mark the position of the horizontal hole (FIGURE 9). Make a dead hole near to the position of the horizontal hole so as to secure the boring machine (See boring machine instructions for diameter and centre distance of dead hole)- (FIGURE10). Position the boring machine and secure it in the dead hole with the special expansion block and take note of the gradient in the following way: Place a boring bar so it is overhanging (3 m), on the upper plane of the bank, parallel to the cutting line (at 1 cm distance) and drop two plumb lines, one along the vertical face and the other at the end of the boring bar. Line up the boring machine with the two plumb wires. Make the horizontal hole.

HORIZ (Horizontal cut)

Following the above procedure, make two holes crossed at 90 _ corresponding with the perimeter of the cut to be made.

II.2. Marking And Making Vertical Holes VERT (Vertical cut)

Place a boring bar in the horizontal hole as a reference. Place a boring bar so it is overhanging (3 m), on the upper plane of the bank and line it up with the lower boring bar using two plumb lines (FIGURE 11). Mark the vertical hole on the upper plane of the bank so it is in line with the upper boring bar (FIGURE 12). Make a blind hole near to the position of the hole so as to secure the boring machine. Position the boring machine and secure it in the dead hole with the special expansion block, making sure the gradient is a perfectly aligned. Make the vertical hole.

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II.3. Remaking of Holes VERT (Alternative for vertical cuts)

The vertical hole must meet up with the horizontal hole. When this happens, compressed air and dust from the vertical boring is visibly vented from the horizontal hole. If however, having reached the correct depth, the holes do not meet up, the vertical hole must be remade taking care it is lined up as described above.

HORIZ (Alternative for horizontal cuts) The two

horizontal holes must meet up

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III. Positioning Machines and Equipment

This section deals with the preliminary operations when using the wire. It is important to carry out well all operations required to obtain the following: - cutting without serious drawbacks - exploitation in full of the wire's cutting and yield potential III.1. Positioning Flywheels

To obtain a high yield performance with the wire, it is essential to position the flywheels correctly. The flywheels guide the cutting profile and avoid making tight curves or worse still "loops" at all costs. (FIGURE 13A) shows how the flywheels can be positioned. There are usually three positions:

VERT (Alternative for vertical cuts)

- high fore flywheel - rear flywheel -lower flywheel

HORIZ (Alternative for horizontal cuts)

-side front flywheel - side rear flywheel . -frontal fore flywheel

The flywheels must all be used and positioned with the following points kept in mind:

- the flywheel must spin freely on its axle. - the rubber lining must be in good conditions. - the flywheel primary axle (where the wire passes) must be perfectly in line with the cutting plane. - Once the flywheel rest is secured to the ground, it must be stable to avoid vibrations deriving from the rotating flywheel.

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III.1.1. High Fore Flywheel VERT (Alternative for vertical cuts)

This flywheel is used to avoid the forming of a loop in the wire during the final cutting phase as it tends to close itself in decreasing radii as it progresses (FIGURE 14); in fact this flywheel holds the wire up and guides it in an almost constant shape from start to end (FIGURE 15). The flywheel is positioned at 40 cm from the upper plane of the bank and sticks out 50 cm from the vertical face. Because of the overhanging position of the flywheel it is of particular importance to make sure of the support system's stability so as to avoid vibrations (FIGURE 16).

III.1.1. Side Front Flywheel HORIZ (Alternative for horizontal cuts)

This flywheel must be positioned in a similar way to that used for vertical cutting, but rotated by 90 _ (SEE PREVIOUS PARAGRAPH).

III.1.2. High Rear Flywheel VERT (Alternative for vertical cuts)

This flywheel is used to ease the exit of the wire from the vertical hole during the initial cutting phase facilitating the transformation of the sharp edge, stressing the wire the least possible. To obtain this, the flywheel must be positioned on the upper plane of the bank at about 1 m ahead of the vertical hole and perfectly in line with the high fore flywheel (FIGURE 17A). Initially, the exiting wire forms an angle of about 30 _ with the upper plane of the bank, but this increases rapidly.

III.1.2 Side Rear Flywheel HORIZ (Alternative for horizontal cuts)

This flywheel must be positioned in a similar way to that used for vertical cutting, but ro

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III.1.3 Lower Front Flywheel VERT (Alternative for vertical cuts)

The purpose of this flywheel is guide the entering wire into the horizontal hole during the final cutting phase. During the initial phase, the wire works at very low tension, because of its own weight and the great friction it encounters with the inner edge, and therefore does not raise (The flywheel is useless at this phase). During the rest of the cutting phase, when the distance between the machine flywheel and the entering point of the wire in the cut has increased, a further flywheel can be added to support the wire and avoid it shredding or hitting the ground (FIGURE 18B). During the final phase, when the run of wire passing through the rock has diminished, even the lower stretch of wire tends to form a loop towards the upper flywheel (this phenomenon can be detected by observing the initial cutting point which "raises" towards the upper exit point)-(FIGURE18A). During the final cutting phase, the lower and upper flywheels make the wire exit at a wide angle (FIGURE 15).

III.1.3 Frontal Fore Flywheel HORIZ (Alternative for horizontal cuts)

This flywheel must be positioned in a similar way to that used for vertical cutting, but rotated by 90 _ (SEE PREVIOUS PARAGRAPH).

III.2 Positioning of Rails

Check there is enough track to complete the cut. This must be about 10% more than the long side of the cut (FIGURE 18bis). In the event there were not enough room, extra gears can be added and if necessary, the rails can be positioned at 90_ with respect to the cut. In extreme cases, the rails can be positioned on top of the bank plane by adding an appropriate series of gears. The room needed for the rails starts at 3 m from the rock face if it is up to 7 m high; It starts at 4 m for greater heights.

VERT (Alternative for vertical cuts)

The machine can be set with the flywheel either to the left or to the right of the rails, depending on the situation: these are then positioned, taking into consideration that the flywheel will be projecting with respect to the rails by about 15 cm (FIGURE 19A).

HORIZ (Alternative for horizontal cuts)

For horizontal cuts/the flywheel is positioned low down and centred with respect to the rails. The central axis of the rails must be offset with respect to the front hole by a length equal to the radius of the flywheel (FIGURE 19B).

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Before positioning the rails, the work area must be prepared, by cleaning it of any various materials and trying to level it as much as possible. Place some wooden planks, 4 cm wide, between the levelled plane and the rails. Initially, only three 3 m segments of rail are available, for a total of 9 m (these are normally supplied free with the machine); As the machine moves back, the segment that has already been run is placed at the rear and so on until the end. It is very important that the rails are leaning firmly on the planks and carefully levelled for its entire length. Without these pre-requisites, the machine would sway while moving back and of consequence the cut would be distorted and the yield of the wire would not be satisfactory. Line up the rails to the two upper flywheels by using a projecting boring bar as a reference.

III.3 Placing the Machine on the Rails

Place the machine on the rails by following the instructions for handling the machine supplied by the manufacturer. Connect upthe electric plug and control panel. Check that the adjustments and command features work correctly. Test the railings by moving the machine along the entire length of the rails already in place. The machine should advance, smoothly especially without swaying or stuttering or jerking.

IMPORTANT NOTE : It is advised to fence off the working area to stop non-authorised personnel from entering.

III.4 Lining Up of Main Flywheel

The lining up of the main flywheel must be done with the maximum care because if not done correctly the wire can disentangle from the flywheels.

III.4.1 Calculation of Gradient VERT (Alternative for vertical cuts)

Adjust the flywheel axle gradient so it matches with that of the cutting plane and with that of the small flywheels (FIGURE 20).

HORIZ (Alternative for horizontal cuts)

Lower the flywheel with respect to the vertical axis.

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III.4.2 Calculation of Fivwheei Axle Position

VERT (Alternative for vertical cuts)

Adjust the flywheel axle position and line it up with the small flywheels (FIGURE 21).

HORIZ (Alternative of horizontal cuts)

Adjust the flywheel axle position and level it with the small flywheels.

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IV Mounting the Diamond Wire

IV.1 Cleaning the Work Area above the Bank VERT (Alternative for vertical cuts)

Carefully clean the work area above the bank (about 80 cm to the right and left of the cut) so as to avoid small stones or debris from falling into the cut. This can cause the wire to break inside the rock and in the worst case, get stuck in the rock, making it impossible to continue cutting.

HORIZ (Alternative for horizontal cuts)

Carefully clean the work area around the bank so as to avoid small stones or debris being dragged into the cut by the wire. This can cause the wire to break and in the worst case, get stuck in the rock, making it impossible to continue cutting.

IV.2 Calculating the Length of the Wire to be Used

Calculate the minimum length of the wire adding the height of the cut to the measurement of the cutting perimeter. For example:

Size of cut:

Depth/Width 20 m Height/Length 7 m

Length of wire: L= (20+7+20+7) + (7) = 63 m

If possible use a single length of wire. If there are smaller pieces available, these can be joined to reach the required length. In this case however, use wires of the same length, of identical diameter and of the same wear (see following paragraph).

IMPORTANT NOTE:

If possible avoid shortening the wire.

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IV.3 Checking the Wear of the Wire

When using a previously used wire, check its condition to evaluate if it will last the entire cut. Check that the diamond is sufficiently protruding and its characteristic tail is in the opposite direction to that of the cutting (FIGURE 22). Check the average diameter of the pearls on the wire. Check the shape of the diamond crown:

- The maximum taper is 0.3 mm - The maximum eccentricity is 0.2 mm.

Check that all the sintered crowns are properly welded to the metal support. Check that none of the pearls are free to rotate on the wire.

IV.4 Inserting the Wire in the Holes

Insert a thin, flexible and strong rope (e.g. a hemp rope) into the upper hole, and tie one end to a cork plug or some other light object which can slide through the hole and drag the rope with it. Make it exit the lower hole, using compressed air or a jet of water if necessary. Connect the diamond wire to the end and drag it through until it comes out the other side by a few metres.

Note for horizontal cuts:

"upper/lower hole": read : "side/front hole"

IMPORTANT NOTE:

Determine the cutting direction with the arrows printed on the plastic or if the wire has previously been used, the diamond tails should be in the opposite direction to that of cutting (the wire enters the cut from bottom to top).

IV.5 Pre-loading the Wire

Prepare the ends of the wire for joining (FIGURE 23). Cut the plastic cover on the steel cable and leave one plastic ring of about 2 mm in contact with the pearl. Let the naked cable whose length is half that of the joint less 1 mm stick out (carefully shear the cable so that the strands are closed). Pre-load the wire with 2 charges per metre so as to close the turns in the cable (anti- clockwise)-(FIGURE 24).

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IMPORTANT NOTE:

The joint can last from 12 to 24 hours of work. After this period it has to be remade by shortening the wire at both ends and restoring the loads in an increasing number according to TABLE 1:

Joint (n_J N_ (loads/m) 1 2 2 2.5 3 3 next ones start again

IV.6 Joining the Wire

Join the two ends of the wire so as to create a loop. Insert a joint coupling on one end of the wire and then onto the other (without loosing the loads and without twisting the wire) and clamp it with the special clamp at about 1 mm from the ends following the following rules:

First end:

Make n_ 2 clampings up to the dynamometric limit Make n_ 2 further clampings at 90 _

Second end:

Make n_ 2 clampings up to the dynamometric limit Make n_ 2 further clampings at 90 _

Make an efficient clamping by paying extra attention to the quality of the joint and avoid making misalignments (FIGURA 25).

IMPORTANT NOTE Use a perfectly working hydraulic tool, with non worn jaws and of the correct diameter. Use best quality steel joints.

IV.7 Placing the Wire on the Main and Small Flywheels.

Place the wire on the rubber linings of the main flywheel and the small flywheels. Run the wire through by hand so as to break the corners.

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IV.8 Pre-arranqement of the Cooling System

Check the cooling system gives an even flow of water throughout the cutting, without sudden breaks or drops in the pressure. Some quarry cutting machines are equipped with a device that is capable of instantaneously detecting any shortages in the water supply, and of consequence suddenly stopping the machine. In fact, if the wire works with a low water supply, its temperature will quickly exceed 70 _ centigrade; a temperature limit after which the plastic becomes irreversibly damaged. If this happens, the wire can be recovered by repairing the plastic through the manufacturer or a laboratory authorised by the manufacturer. If, however, the cutting proceeds under these conditions, the pearls will be able to move freely on the cable, gradually slackening the cable. Eventually the pearls could enter the cut wrongly and jam in the rock. If this happens, the wire stays jammed in the rock and cutting cannot continue. Problems can also arise from excessive lubrication. Excessive amounts of water can in fact cause aquaplaning that makes the pearls slide without abrasion as a slim layer of water is created between the two. Correct lubrication can be obtained by carefully following the instructions which is fundamental in reaching high yield and avoiding the problems described above.

During the initial cutting phase, position a jet of water so that it penetrates the horizontal hole with pressure. This way, the wire drags the water along the hole and lubricates the lower corner. Position a second jet of water near the vertical hole so the water can penetrate inside (FIGURE 15A).

Note for horizontal cutting: "horizontal/vertical hole" read "side/front hole"

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V Starting the Cut

V.1 Slight Pre-Tension of Wire

Slowly draw back the machine until a slight tension is created on the wire. Slight tension on the wire should stop the flywheel rotating freely. Place the small flywheel/s at the side of the machine so as to obtain the broadest arc of contact possible between the diamond wire and the flywheel.

V.2 Running the Wire Through by Hand

Run the wire through by hand until the corners are slightly rounded and the loads are distributed throughout the length (at least 2 complete turns). Under these conditions, the sliding strain is reduced and the flywheel can start rotating at low speeds using the engine.

IMPORTANT NOTE:

Be careful not to put excessive tension on the wire and therefore avoiding immediate or later breaks.

V.3 Checking the Rotation of the Wire

Visibly mark a point in the wire (lower part) with a piece of sticky tape so rotation can be observed. Run the wire through by hand. Starting from the lower flywheel, the wire must rotate by one turn for every 3 m it advances (one rotation for every 2 - 4 m is acceptable).(FIGURE 27)

Note for horizontal cuts:

"lower flywheel": read: "side flywheel side entered the cut"

IMPORTANT NOTE:

The constant rotation of the wire on its axis is an essential requirement to fully exploit the yield of the pearls and avoid ovalization.

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V.4 Starting the Machine in "Manual" Position

Prearrange the machine in "MANUAL" mode and with the flywheel speed set at lowest. Start the flywheel rotation, helping the wire by hand. Once the wire is rotating normally, gradually increase the speed up to operation speed.

IMPORTANT NOTE:

If the flywheel slides when the wire has stopped, stop the machine immediately. Under these conditions, the plastic on the wire and on the flywheel melts.

Check that the wire rotates freely without sideslipping or vibrations.

V.5 Rounding Corners

The starting of the cut is a very delicate phase. Given the wires ability to remove large amounts of material from corners, the machine tends to move back very quickly. Move back as slow as possible and keep the tension on the wire at a minimum but avoid disentangling from the flywheels. If, while exploiting the possibility of cutting quickly, the machine moves back too quickly, then the pearls get worn into a conical shape and the overall yield collapses.

V.6 Intermediate Pauses during the Cutting

When it becomes necessary to pause during the cutting, follow this procedure:

1) Stop the machine moving back.

2) Let the wire rotate for about one minute so as to reduce the wire tension.

3) Stop the flywheel.

4) Before the flywheel has completely stopped, move the machine about 4-5 cm towards the cut so as to completely relieve tension on the wire.

Under these conditions, the wire can move freely in the cut, and the cutting process can restart whenever needed.

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V.7 Moving and Removing the Rear Flywheel

After a short while, when the wire has broken the corner exiting the cut, the rear flywheel has to be pushed forward (FIGURE 17B see chapter 111.1.2- VERT). A little later, when a great radius has formed from the exit of the cut, the flywheel can be removed (FIGURE 17C see chapter III.1.2-VERT).

V.8 Changing the Positions of the Water Jets

As the form of the cut changes, move the initially positioned rear water jet forward, and add another further forward so as to continue lubricating the wire. If the lubrication is correct, the wire exiting the cut creates an almost vaporised jet of water, because of the high speed and emits a characteristic sound, almost a hiss, which is a sign of the wire's good cutting quality (this is true even with only the rear jet, which is the fundamental one)-(FIGURE 26B see chapter IV.8). In this case, any variations in the water flow causes a corresponding alteration in the characteristic noise. This empirical method is easy to use and is advisable so as to recognise a fair number of problems "by ear".

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VI Continuous cutting

VI.1 Switching to Automatic Operation

Switch to "AUTOMATIC" operation mode and set the following cutting parameters on the machine: - flywheel rotation speed - flywheel engine absorption

At this point, the machine moves back to keep the flywheel absorption constant. For a few minutes check that the speed that the machine moves back with, stays within normal minimum - maximum limits. If the wire is very sharp, the speed could be too high. In this case, the wear on the wire could become excessive and irregular. If so, reduce the absorption value previously set. If the wire does not cut well or not at all, then the speed at which the machine moves back is too low. In this case, check the wire and try to determine why the wire is not cutting well.

Periodically check the following:

- that the withdrawal speed of the wire is correct. - that the wire does not vibrate or sideslip. - that the wire does not turn on itself.

and intervene if necessary.

VI.2 Periodical Checking and Replacement of Joint

Check that the joint is in good condition every 2 hours. Remember to remake the joint every 12-24 hours according to TABLE 1, paragraph IV.4 (pre-loading the wire). If possible, avoid shortening the wire, even by adding transmission flywheels. Each time the joint is remade, make at least one complete turn of the wire by hand, checking that it runs freely through the cut and then start cutting again in the way previously described.

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VI.3 Checking and Repositioning the Cooling System

Remove the water jet that was placed at the entrance of the horizontal hole. Place one jet of water for every 50 cm in the upper part of the cut, starting from the vertex of the cut. The jet position must be periodically changed as the shape of the cut changes. Each time carefully check the jet at the vertex and then position the others in the way described above (FIGURE 26B see chapter IV.8).

note 1 for horizontal cuts:

"upper part of cut" read : "side part of

cut"

Note 2 for horizontal cuts:

Little by little, as the cut gets bigger on the side face, fill it in with hemp rope so as to stop the cooling water exiting completely.

IMPORTANT NOTE:

- Absolutely avoid letting the wire work without water. - Avoid excessive water flow and an aquaplaning effect.

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VI.4 Checking the Wear of the Wire and the Advancement of the Cut

About every 2 hours, stop the wire and, running it by hand, check its wear. Take note of

the following data:

- linear velocity of wire - working time elapsed from the start of the cut (hh:mm) - length of wire (m) - position (x,y) and diameter of flywheels (m) - position (x) of main flywheel (withdrawal) - position (x/y) and angle (J of wire entering and exiting the rock - examine the upper profile of the cut (points x y)

Make a graph representing the profile of the cut.

- calculate the area cut (m2)

- calculate the average cutting speed (m2/h)

Take note of the condition of the average wear of the pearls:

- projection of the diamond (mm)-(FIGURE 22 see chapter IV.3) - average diameter of pearls (mm) - taper of pearls (mm) - eccentricity of pearls (mm)

NOTE:

During the pause, check the temperature of the wire. If the wire is hot, check the position of the jets (correct these if necessary) and the water flow (increase this if necessary).

VI.5 Inserting Boring Bars into the Cut (Normally, for horizontal or vertical cuts, when the rock, because of internal tension, tends to close the cut)

If the rock tends to close the cut (typical with horizontal cuts due to the weight of the bank), insert boring bars, of corresponding diameter, into the cut as its vertex moves. This avoids the wire being pinched (FIGURE 8 see chapter 1.6).

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VII Exiting the Cut

VII.1 Replacing the Wire

When the vertex of the cut is at 2 m from the vertical face of the bank, replace the wire with a previously used piece (or with a stronger wire) of lesser diameter.

VII.2 Starting the Final Cutting Phase

Set the machine to "MANUAL" mode and reduce the advancement speed to the minimum so as to release the tension on the wire.

VII.3 Exiting the Cut

During the final phase, the profile of the cut approaches a tight line between the two flywheels (lower and upper). As the wire approaches the exit, gradually reduce the tension, finally bringing it close to zero. Under these conditions, the wire exits the cut without a whiplash effect and remains on the flywheels.

VII.4 Recovering and Storing Wires Used and Equipment

Carefully clean and dry the wire and the equipment used. In particular, wind the wire in a skein and tie it up, then hang it up in a dry and sheltered place. Avoid exposing it to extreme temperatures (min. 5 _ Centigrade - max. 50 _ Centigrade). If necessary, re-plasticise the wire at a workshop authorised by the manufacturer.

IMPORTANT NOTE:

The diamond wire is a high value tool. During usage, treat it adequately, being careful to:

- NOT TREAD ON IT - NOT TWIST IT

If the wire becomes twisted, absolutely avoid pulling it. Proceed calmly and gently unwind the skein, laying it out for its entire length and rewind it

back onto the skein.

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VIII Turning Over and Cutting Up the Bank VIII.1

Detaching the Bank

Continuously bore the sides not cut by wire and blow it up with explosives (SEE Paragraph

1.1).

VIII.2 Moving the Bank Away with a Hydro-Bag

The hydro-bag is a tool used to move the bank away from the face by about 25 cm. It is made from a steel bag that is placed in the gap made after the explosion (FIGURE 30A). Thanks to the pressure of the water let into the bag, it expands and pushes the block away (FIGURE 30B).

VIII.3 Turning Over the Bank with Hydraulic Jacks

Once the bank has been moved away by about 20 cm, it is ready to be turned over. Prearrange a bed of earth and debris to soften the impact with the ground when it is turned over. Insert hydraulic jacks in the upper part of the crack so as to push against the bank and turn it over (FIGURE 31).

VIII.4 Sectionalising into Blocks

Once turned over, sectionalise the bank into commercial size blocks with the continuous boring method previously described (FIGURE 32A-32B) or use the diamond wire arranging the flywheels in a similar way to that used for vertical cutting (FIGURE 32C).

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IX Diagnosis and Solution to Problems

Symptoms Problem description Cause of problem Solution

1 The pearls are

worn into conical shapes

The pearls remove too much material with the strain concentrated on the upper part

Withdrawal speed too high with excellent cutting capacity

Reduce withdrawal speed

Cutting in opposite direction to that printed on wire

If discovered in early stages, reverse rotation direction, If in advanced stages, reduce withdrawal speed and complete the cut

Incorrect type of wire: nsufficient number of pearls per metre

If discovered in early stages, re-plasticise with more pearls/m. If in advanced stages, reduce withdrawal speed and complete the cut

Cutting speed too low and therefore cutting capacity increases and pearls are worn into conical shapes

Increase the cutting speed and reduce the withdrawal speed

2 Wire is worn into helical shape

The wire does not rotate on itself correctly in the cut

Withdrawal speed too high with respect to cutting capacity

Reduce withdrawal speed.If the irregular shape is not too excessive, wear can be made uniformby cutting for a few hours without loads, otherwise re-plasticise

Incorrect pre-loading Pre-load the wire again following chapter IV.5

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Problem Symptoms description Cause of problem Solution 3 Wire worn flat

and eccentric in linear form

Wire does not rotate on itself at all

Loads on wire are nsufficient or absent

Remake the joint with the correct number of loads. If ovalization is excessive, re-plasticise the wire

The wire was not loaded enough or not at all

Remake the joint with the correct number of loads

4 Non-plane cut Incorrect movement of wire

Incorrect machine -holes - flywheels line up

Line up machine - holes -flywheels again

5 Some pearls rotate or can move on the axis with respect to the wire

Mechanical decay of polyurethane

Temporary shortage of cooling liquid raising temperature beyond maximum imit (80 °C). Wire accidentally hit the ground or another fixed object during cutting.

If the defect is found on a length of wire with a maximum of 20 pearls, remove the piece of wire in question, shorten it, reload it and rejoin it.

If the defect is found on a few sparse pearls, remove them one by one: Break them with a hammer without damaging the cable and protect the empty space with sticky tape

If the defect is found in many pearls, re-plasticise the entire wire.

6 The wire is hot (can be checked during pauses)

Insufficient cooling

Water supply badly positioned or low or no water supply

Check the positions of the tubes and if necessary move them, being especially careful with the jet at the vertex. Check water flux and if necessary increase it.

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Symptoms Problem

descriptionCause of problem Solution

7 The wire oscillates in a helical way

Harmonic resonance of span of wire

Resonance period equal to or a submultiple of the span

Reduce the cutting speed until the oscillation disappears, then gradually increase speed until optimal speed has been reached, f necessary, take note of the flywheel positions at side of machine.

8 Wire disentangles

The flywheel/s prime the vibration of the wire

Rubber lining of flywheels deteriorated

Replace the deteriorated rubber ining on the flywheels

ncorrect balance of flywheels

Check and if necessary, replace the flywheel bearings

ncorrect line up of small flywheels and main flywheel

Line up small flywheels and main flywheel

9 Difficulty restarting the wire after a pause

The wire was under too much pressure during a pause

Cutting interruption procedure was not followed

Move the machine forward to release pressure until wire cDan be moved by hand and then restart as normal

10

High machine absorption with very low or no withdrawal speed

Diamond not projecting (feel with fingernail in opposite direction to that of operation)

Speed of wire too high

Reduce speed of wiDre by 10 -20%

Work for 1 - 2 minutes without water (take care to not overheat the polyurethane)

Throw sand into the cut or saw cement blocks which are rich in sand

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Symptoms Problem Cause of problem Solution description 11 Normal Aquaplaning Excessive flow of Reduce the flow of water whilst

absorption with water guaranteeing a correct

very low or no lubrication of the vertex of the

withdrawal cut

speed

Pumping Water is sucked

into Carefully drain the ground of

effect. A the cut by the wire

in water with a pumping system.

puddle of excessive amounts Close the flow of water until the

water has cut is drained of excess water.

formed that

covers the

entering wire.