case study of core and pluge preparation

7/31/2019 Case Study of Core and Pluge Preparation

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Experiment no: 8

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Aim: Case study of core and plug preparation

Introduction:

When a piece of rock or core is wanted to be used for analysis as a sample in the laboratory, several steps,

as per-processing steps, should be considered on the sample to be prepared for experiments. The main

pre-processing steps are follow:

(1)slabbing : the cores need to be slabbed with the aim of making the rock structure visible. this can

simply be done by sawning down the middle of the rock and cutting it at desired length.

(2) Plugging: one can drill the plug at every one foot of the core.

(3) trimming: both end of the plugs and core samples can be trimmed in order to produce high quality thin

sliced samples without disturbing the structure of the sample.

Core Slabbing:

Core slabbing is the first step in the preparation of samples for core laboratory experiments. The radialcore slabbing saw is a machine for cutting rocks into the smaller parts. . This is basically for cutting a bigsize outcrop rock into the smaller parts and/or cutting the longer cores to the shorter ones. Radial coreslabbing saw is designed for diamond cutting discs only, which is connected to the motor with a shaft andtwo pulleys and the use of the cooling waters improves the slice quality and cutting speed and reduces theheat which is produced by sawing process. Figure below shows the core slabbing machine.

Fig. 1

However, students should consider the following safety notices:1-This machine must only be operated by qualified personnel specially those who has had the operation

training and the safety regulations.2-Protect yourself from any splash produced by wearing a suitable overall.


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Experiment no: 8

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Machine Description:The machine has a motor which supplies the rotational motion for sawing. The main machine parts are:

Radial sawElectro motorShaft, pulleys and rimAdjustable tilting tableCooling system, including

pumps, water supply, flexible pipes

The rotational motion transmitted by two pulleys from electro motor. At either side, there are three

different stepped pulley couples. The speed of motion can be adapted by positioning the compound

diamond rim on the suitable stepped pulley couple on the electro motor and saw system. The dimension

of rock sample should be smaller than the max height of saw from table to be cut electively. Bigger rocks

should be broken to a proper part with other methods. One drawback of this machine is its noise. Themachine noise level is around 70 dBa. During the cutting process, the noise level depends on the material

to be cut, the type of disc used, the rotation speed and the cooling.


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Experiment operation:

The procedure for cutting a given sample is as follows:

If the rock is big then it should first be cut by another method

Put the sample on the table

Check the tension on the pulleys

Adjust the direction of water line on both saw and sample

Check water tanks and fill them if they are empty

Start the water pump and check the direction of water and check the flow

Start the saw by pressing the start bottom

Cut the sample by screwing up and down of the saw and pushing the sample table of machine

Press the stop button

Unclamp the core sample.

However, in working with the machine consider the following safety issues: (i) prevent touching of sawwith the machine sample table, because of damaging of saw, (ii) protect yourself from any splash andwater drops by wearing overall and safety glasses.

You should consider the appropriate rotational speed. The motor shaft rotates at 1,440 rpm. When the beltis on the central pulley either on motor side and disc side, the disc rotates at 1,440 rpm. When the belt ison the small pulley on motor side and on the large pulley on the disc side, the disc rotated at 2,160 rpmand finally when the belt is on the large pulley on motor side and on the small pulley on the disc side, thedisc rotated at 960 rpm. The schematic diagram of pulleys at both motor side and disc sides are illustratedin Fig. 2.

Figure 2:Motor 1 440 rpm Spindle disc holder

Figure 2: PulleysCutting linear speed in meters/seconds versus disc diameter and speed are shown in Table 1.


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Table 1: Cutting speed and disc diameters of core slabbing machine

Disc diameterDisc rpm 300 350 400 450 500

960 15 17.5 20 22.5 251440 22.5 26.5 30 34 37.52160 34 39.5 45 51 56.5

For cooling of the saw and sample during the operation, water is used. Water is pumped from water tankand poured directly to the sawing position on the sample. Then, the used water goes to the water tank.Water tank is composed of to different tank. The recycled water first enters to the first tank, and afterprecipitating of cuttings into this tank, the fresh water overflow to the main water tank.

Maintenance

Keep the machine clean.Do not let water and waste in the tray.Check carefully the v-belt and its strain.


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Plugging using plug drill Press machineThe core cutting machine is designed to cut specimens from cores of between 4 to 6 inches, or fromblocks of a similar size. The produced plugs are in two different size of 1 and 1.5 inches. This machinecanbe installed on any table (Fig. 3). By screwing down of a hollow plug drill, plugs are cut from thesamples.

However, students should consider the following safety notices:-The core cutting machine should only be used by qualified operators who have been suitably trained inhow to produce the quality of cut required under the prescribed safety conditions.

Machine Description:The machine can accommodate cores measuring from to 3. A swivel joint with a tap allowsInternal irrigation of the core drill and a hose fitted with a tap allows external irrigation of the core drill.The speed can be adjusted by repositioning the belt (1800 rpm2500 rpm3500 rpm) like core slabbingmachine.The machine comprises of:

clamping standcolumn

Spindle-Motor unit

adjustable tilting table

protective housing

clamping unit

recycling tank


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Table of machine has a rotating capability up to 45. This capability causes that user can make plugs fromany part of slab even deviated sides.

Experiment operation

Check the tension on the pulleys

Check the direction of the spindle

Fill the recycling tank

Screw down the core drill and lock it in place

Mount a core sample and lock it firmly in the clamping unit

Adjust the lower stop on the core drill. 1-2 mm before the end of slab is sufficient for prevention ofplugging the sample in plug driller. . Touching of the driller with table causes severe damage to thedriller.

Close the core drill protective housing

Press the Start button

Open the irrigation taps

Check the flows

Cut the core sample

Press the Stop buttonUnclamp the core sample

Speed of rotation can be adjusted by changing pulleys. The procedure for this operation is as:

open the pulley cover

loosen the 2 locking screws and pulley tension lever

pinch together the two sides of the spindle belt

change the position of the belt

tighten the belts with the lever and lock the two screws in place

close the cover

If the tension of pulleys is not sufficient then the belt should be changed. The procedure for changing thebelt is as follow:

make sure that the machine is disconnected

open the pulley cover

loosen the two clamping screws and the belt tensioning lever

pinch together the two sides of the spindle belt

change the belts

tighten the belts with the lever and lock the two screws

close the cover

Maintenance

keep the unit and the protective housings clean

remove debris and core particles

remove sludgeclean all moving parts

change the cooling fluid as soon as it is dirty

make sure that the machine is disconnected

remove the pump and the waste pipe from the recycling tank

empty the tanks

clean the tanks and the separatorsfill the tank with cooling fluid

refit the pump and the waste pipe to the recycling tank


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Trimming Core PlugsAfter preparing plugs in core drill machine, all of them should be cut into desired size. This can be doneby trimming machine. Trimming machine is a bench model designed to produce fast, high quality thinsliced samples from all materials without disturbing the structure of the sample (Fig. 4).However, students should consider the following safety notices:

Touching any resinous cutting wheel can be dangerous.

The machine is fitted with safety devices which prevent the wheel from turning when the hoodis open

This machine must only be used by a qualified person who has received the proper training required toachieve the quality of cut and the high standard of safety envisaged by the manufacturer.

Figure 4: Trimming core plug machine

Machine Description:The basic model can work either in manual feed or with an optional hydraulic automatic feed which is

driven by the domestic water supply (Minimum pressure 1.5 bars). In the automatic mode, user candetermine the speed of rotation of saws. The machine consists of two radial saw that can work togetherand cut both end of pugs simultaneously. Each cuts needs nearly 0.2 litter cooling water. This machine isdesigned to work with all types of cutting wheel (resinous - diamond - boron carbide) and variousaccessories and adaptations enable samples or core sections to be cut lengthways. These include cradlesor devices for holding the samples configurations using two wheels which allow parallel-sided sections ofcontinuous length to be cut in a single operation. The machine is fitted with a safety cut-out switch whichcan be reset, or rewound should there be no power, as well as a gradual starting device. When the cover is


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open this safety switch open the electric current and the machine dont work. The use of passivated wateris strongly recommended to avoid corrosion.

Experiment operationThe machine can work in both manual and automatic mode. By setting two lever taps on the body ofmachine, three situations are achieved. The lever taps allow the wheel (saw) to advance or return.

quick back mode: in this mode the saws go back quickly and positioned at the start point. Thismode can be achieved by setting both taps down.

stop manual: in this mode user should handle the position of saws for trimming the plugmanually and can be achieved by setting top tap to up and bottom tap to dawn

automatic feed: in this situation samples are trimmed automatically by the machine. The rotationalspeed of the saws can be adjusted by the Movement regulator beside the lever taps.

Manual mode

Steps for operating in manual mode are as follows:

Press the start bottom

Set the taps to Quickbackposition, at the end of the race, the lever is independent of jack,

Set the taps to the "Manual stop" position.

Adjust the direction of water line on saw and sample



Close the protective housing of machine

By moving the saws to front start trimming of the sample

Press the Start button

Press the Stop button

Unclamp the core sample

Automatic feed (optional)Steps for operating in automatic feed mode are as follows:

Press the start bottom

Set the taps to the Automatic feed " position

Adjust the direction of water line on saw and sample



Close the protective housing of machine

Gradually open the movement regulator until the required feed rate is obtained.At the end of the cut, turn the taps to the "Rapid return position.

Press the Stop button

Unclamp the core sample


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Maintenance:Apart from keeping the machine properly clean, no specific maintenance is required. Make sure that anysediment or waste matter is removed from the tank before starting. Change the fluid according to thefrequency of use and its deterioration over time (shelf life).

case study of core and pluge preparation

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