SOFTWARE METHOD OF BLAST RESULT ANALYSIS BY GIANT MINER

Technical article

By: Taiwo Blessing olamide

INTRODUCTION

Blasting result assessment is very important to justify the efficiency and Productivity of every blasting operation. This is also to view the need to optimize the blast design in order to add value to downstream operation and reduce the cost of transporting run-off-mine, prevent transportating waste materials www the mine to the mill, minimize the cost of crushing and separating the gangue material from the concentrate in case of metallic and gemistic mining industries. It become important that analysing the blasting result using various available software that helps the mine manager to meet up with the production rate per day at the lowest cost implication is imperative. Most mines are less concerned about the result of Blasting but still keep complaining on the low profitability of their mine and low efficiency of the working equipments. Poor loading with long loading cycle time along side with continuous separation of Boulders consume Diesel and also limit the loading equipment efficiency. 

Image analysis delineated Result from Wipfrag software

Some mine employs the use of hydraulic breaker for further breaking of boulders separated from poor blasting, while others industry engage in secondary Blasting operation. Blasting operation can be done in such as to limit secondary fragmentation cost through justification of blast output result and checking the status of each blast result to optimize the blast parameters such as to produce result that blend with the gape of the primary crusher. 

This makes blast Fragmentation analysis and other Post blast checking softwares like WipFrag software, Split desktop, Fraglist software among others Important.

Nevertheless the use of o-pit blast software, Kuz-Ram model in adjusting the blast design is also important.

Find below a simple and Introduction explanation to Blast result analysis.

BRIEF INTRODUCTION ABOUT WIPFRAG SOFTWARE

Visit WipFrag software website here

WipFrag analysis is one of the many available software use in analysing blast Fragmentation. Mostly, after Blasting, the Mining Engineers are interested in checking the Blasting aggregate uniformity and size distribution which help both in measuring the blast efficiency and the digging rate of loading equipment during loading. It is believed that, a good Blasting is that which has <5% oversize and <5%undersize.

Also, from the result of fragmentation analysis, we can determine whether their is blast misfire or improper detonation of explosive charge which can be detrimental to both mine workers and loading equipment. This makes fragmentation analysis very important.

WipFrag software make use of empirical model and other intrinsic model to justify blasting image from the view of photo analysis.

The software recieve blast picture snapped with a scaling object and provides the size distribution graph for a typical Blasting.

The software base on it design program consist of image analysis program code which  by scanning, generates an image size distribution which is justified by the scaling object provided in the picture.

 HOW DOES WIPFRAG SOFTWARE WORKS

Getting blast image from the mine site is the first thing to do.

The image is collected with either phone camera or drone as shown below

 After Blasting, excavator can be use to spread the muckpile in case of heap pile.

Then a scaling object is placed on the blast pile.

The scaling object can be helmet, frame of known dimension or any object with define dimension.

 In snapping the picture, the angle at which the picture is been snapped is very important, likewise the distance. The distance must not be to far and also the camera inclination must not be to dip in.

After collection of blast images,

The image is uploaded into the software.

The scaling object dimension is imputed.

Then, the scaling object image dimension is measure with an inbuilt dimensioning ruler provided by the software. See the image below

 After this, the mesh scan of the image particle size is adjust to fit in for both large boulder and fine particles. After particle mesh adjustment had been done, the graph for the size distribution is generated automatically.

Interpretation of the graph

As have said earlier, blasting Engineers are concerned with the improvement in productivity of the mine.. therefore analysing the size distribution to know if the undersize produce is to much or the oversize is to much is done on the  particle size distribution graph.

The provided graph is like this shown below,

The graph gives the particle size range and their percentage in the pile. The software also provide data like the 50% passing size and other information about the blast.

The X50 denotes the Fragment size that make up the 50% material passing opening in the blast result.

The X80 represent the Fragment size that make up the 80% material passing opening in the blast result.

The graph interpretation is also display at the right hand side in tabular form. 

This result provides other parameters such as uniformity index, Xmax, X10 to mention few.

CONCLUSION

Using analysis software will not only provide you with data to work with, it will also help you to make necessary adjustments to your blast design and output.

Haul Truck falling in a mine and Blasting relation with rock: Getting high Mining Profitability and Safety Record Assurance

Mining Engineering is the best field to be as we are concern with how the valuable Mineral deposit is Exploit from the earth crust for the benefit of manufacturing man's want.

Working bench and safety issue

Working ore deposit on a single bench may likely be hazardous if proper care is not taken to check Safety management. The failure of rock depend strictly on the bench slope angle and the discontinuity condition of the rock. Appearance of fracture and fault Vin rock mass can result from natural features and also artificial factors including poor Blast design, poor mine design among other issue relating to mining operations.

To avoid such accident like truck failing, Rolling down of boulders from level to level it important to ensure benches are wide enough and design with sufficient beam. A beam is a safety distance space left at both front and edge of a working bench width and haulage vroad (Ramp) to safely guide haulage trucks from failing into the pit and also guide rock boulder from rolling down the benches. Accident is an unplanned event and can cause high damage on both workers and equipments, therefore proper bridging of haulage road will help to prevent truck failing into the mine pit during turning time, revealing time or traveling time.

How to avoid Truck falling in a mine

1. Building beam: designing a beam is the easiest way to prevent truck and boulder fall. A beam according to standard rend in with between 10-15ft, and can also be 2-4.5% of the haul truck width, a beam should be about 0.45-7 of the haul truck Tyre in height.

In most working time, traveling truck in a bit to manover or turn can miss calculation and drone into the pit due to the dipping elevation Condit of the pit. Thou we can't just mine material without moving them to the processing plant, therefore we require a ramp or haulage road that will provide access for truck into the pit. In achieving this, we require the working bench width to be wide enough to accommodate the loading equipment turning radius, the haul truck width, the end beam width, and the front beam width.

For local quarries, where materials are stock pile in attender, an attender sometimes can be between to pits or at the end point of the pit which requires the haul truck to travel through various in between pit ramp, in such case haul truck are highly prompt to falling as the level of riskbis high. Such Quarry required the following safety Tips to avoid falling of trucks into the pit:

a. Increase in between pit haul road width to about 2.5 of the haul truck width such that two trucks can pass with half inter distance space free.

b. Building of beam at the end and front of the haulage road, this can be done using cement bag filled with overburden material. The beam bag should be  two width step and three step up to serve as guide for truck and stopper for boulder falling. Falling of boulder from moving truck or as a result of found stress readjustment under load can break workers head or damage body part seriously.

c. Finally, checking of road conditions for shear off edge or floor heave should be done before daily job by the mine supervisor.

2. Regulations of Fleet time such that each truck can access road at once in case of narrow width ramp.

Most cases may result in small width road due to poor initial design. Such road can be close down or increase a bit. With increment decision, the mine manager should design a proper fleet that make one truck travel per time on the road. In any way it may be, the road width must be at least 1.5 of the truck width, with beam in place at the two edges.

I conclude this with a word of advice to all mine supervisor who are in charge of all workers in every section of the quarry, supervisor are to supervise and shun unsafe act, good supervision will not just safe company from loss but will also safe them from accident. Let all supervisor assign as many as needed assistance supervisor among workers to ensure the full compliance of workers with company safety management system. Also, most company COO, CEO and management with no safety management system (SMS) should make provision to adopt one.  SMS helo to build a comprehensive approach through 10 key elements to garantee safety in the mine. This 10 elements approach are:

1. Policy: management build safety policy that is transparent to all workers and personnel working in the mine. This safety policy states clearly the company goal and objectives on safety assurance. It gives attention to opening and closing time of the mine, Blasting time among others.

2. Management structure: SMS make clear the company structure and provide job description of all officials in the mine.

3. Operation: SMS give information about how specific mining operation is carry out in the mine in accordance to National policy and regulations

4 hazard management: SMS of every company provides a comprehensive way of identifying hazard, assessment of hazard and management of hazard in a systematical way. Some company design their own WHAC (Workplace hazard assessment Condition)

5. Incident Management: How mine incident is to be managed

6. Workers participation

7. Maintenance

8. Training and competency

9. Emergency response

10. Record keeping.

All this 10 elements help a company to avoid unwanted and unplanned accident which can subject workers life into calamity or damage. Adopting a SMS in mine and local company is a strategic way of preventing hazard and lower the level of risk mine workers are exposed to in the mine.

Blasting relationship with rock strength

Thou we like to mine orebody but we do that with understanding of what the earth response can be. Earth is a spherical body with stable and equilibrium forces with all around balance stress field. As we mine will tend to alter the state of Earth rest, the balance of pit slope and the control of shift in tectonic plate.Thou orogeny and some other mountain reef shift may contribute to wall failure most time depending on region. Rock excavation affect the state of rock stress distribution as the concentration of normal and shear stress become altered as excavation is created into an intact rock. Most Blasting operation don in discontinuous rock mass tends to be highly risky due to the possibility of fracture daylight which can finally terminate the competency of a plane and makes it detrimental to mine worker safety. What discontinuity does to slope is to weakens both the internal resistant strength of the rock (cohesion) and decrease the internal angle of friction which dictates the stability of such plan at initial. 

Generally when it comes to rock excavation, failure can occur in three ways, Plane failure, wedge failure and toppling failure. All this failure has a specific required criteria that prompt there occurrence.

During Blasting we are concerned with ensuring that none of this condition is fulfilled after blasting so as not to call for a total of partial close down of the mine by rock fall. A fall in rock mass of weight less than 0.25kg at a projectile height is capable of disability if not prevented. Most rock fall occur after fragmentation, as rock mass tends to readjust stress with it's new environmental condition after Blasting.  So as an engineer in charge of Blasting or mine design, we check on both the rock characteristics, dilution control factor and the possibility of ease loading without fleet delay and damage to crestee bench floor during design.Avoiding all possible overbreak and backbreak is the main aim of powder control. Powder factor must be that optimum to ensure good fragmentation and stable bench wall. As good fragmentation with poor wall result into poor operation due to the possibility of total closure at wall caving or total closure by Ministry of mine after an occurrence of brutal accident.Mine safely.

SIMPLE EXPLOSIVE SAFETY TIPS

Safety tips in Explosive transportation and storage

Explosive is sincerely known to be highly dangerous due to the high energy emission at detonation.

Explosive can either undergo detonation or deflagration,

Depending on the type of Explosive, the intensity of the initiation energy and the present condition and sensitivity level of the Explosive.

Explosives had been design from manufacturer production point to be safe under some specified conditions.

For this reason, explosives are classified into high and low Explosive base on sensitive and energy Strength.

It also classified into primary, secondary and tertiary Explosive base on its working principle. Some country also further classify Explosive into class 1, 2...

All this attempt was to ensure good Safety storage and proper handling understanding.

Most Explosive may become unstable under temperature, handling status, environmental condition and storage. 

Having the knowledge and understanding of Explosive is not limited to just mining and Explosive Engineers. Having some simple understanding about Explosive and other Blasting accessories as an individual working in mine site, Explosive manufacturering companies, Agrochemical industry, and other related companies won't only add to you but also garantee safety management system.

Thou according to Explosive Acts and regulations only competent and certified professional person are allowed to relate with Explosive.

But in case if an ordinary person or someone working in other profession not related to Explosive come in contact with Explosive or Explosive unsafe act and working condition, having a little knowledge about this will go along way.

Safety tips on Explosive transportation, Safety tips on Explosive storage and 

Safety tips on Explosive handling and usage

The initial stage in carrying out a risk assessment is to identify the hazards associated with the explosives and their handling, storage and use in the workplace, and transport both internally and between sites. Information to help identify the hazards is available in the relevant regulations, from the manufacturer/supplier of the product and from a number of other sources. All relevant sources of information should be examined to help with the risk assessment process.

The following should be considered when identifying the hazards:

1.Where are the explosives transported and stored?

2. How are they used and transported?

3. What are the potential sources of ignition and detonation?

Where pyrotechnic articles such as fireworks are stored, e.g in shops, the primary hazard that needs to be considered is fire or accidental ignition. Do it yourself superstores would also need to consider the additional hazard presented by other flammable materials, such as white spirit.

Organisations storing high explosives would need to consider a wider range of issues, such as ignition by:

✓naked flames

✓electricity (including static electricity and electromagnetic energy)

✓sparks from mechanical or frictional contact between metal surfaces

✓heat and temperature

✓pressure

✓impact and friction

✓chemical incompatibility between certain substances such as contact with bare rusted metal

✓contamination by grit

✓reduction of stability over the life of the explosive.

The following should be considered when identifying the hazards.

✓Where are the explosives used and stored?

✓How are they used and stored?

✓What is the potential for hazardous or explosive atmospheres occurring?

✓What are the potential sources of ignition and detonation (including the likelihood of electrostatic charges, etc)?

Evaluating the risks from explosives

Once the hazards related to explosives have been identified, it is possible to consider and evaluate the risk of an explosion or fire incident occurring.

The person responsible for evaluating the risk factors should consider:

✓the possibility and likelihood of fire or explosion

✓the quantities of explosive materials (and other dangerous substances) stored on the premises

✓the structures and property that could be affected

✓the number of people on site

✓the potential severity of the damage to people and property

✓any existing safety or control measures

✓the competency of people in the workplace and involved with transport

✓any accident and emergency procedures in place

✓information available to employees and other people on site.

When evaluating the risks associated with explosives, the assessment must consider all possible effects including, but not limited to, the effects of blast and overpressure on persons, property and the environment, the projection of debris or fall area of a collapsing structure, and the potential for ignition of other flammable substances.

Serious risks should be dealt with immediately. All other risks should then be dealt with in priority order, depending on the seriousness of the risk and the likelihood of an event occurring.

The results of the risk assessment should determine the control measures necessary to prevent or adequately control any risk from fire or explosion.

Control Measures

The principal issue to be addressed in the safe storage and transport of explosives is that of preventing the accidental initiation of explosives. Primarily, this involves keeping sources of ignition away from the explosives. It also involves controlling the presence of explosives, especially in areas of activity, e•g places where work is carried out or where people or other traffic move around regularly.

The control measures (precautions) that need to be employed will be identified during the risk assessment process. These may include some or all of the following:

✓excluding naked flames

✓excluding sources of electrical energy which could produce sparks or otherwise initiate the explosives

✓preventing electrostatic charge build up and discharge

✓preventing accidental initiation from frictional or impact energy; packaging design should reduce static and shock when transporting or storing explosives

lightning protection

✓preventing accidental contact between exposed metal surfaces

✓preventing accidental contact between explosives and exposed hot surfaces

✓preventing contact between explosives and chemically incompatible substances

✓preventing contamination of explosives and ingredients

✓ensuring a suitable distance between explosive stores and site traffic or active areas of the site

✓minimising the time that explosives are in an unstable intermediate state before final processing

✓avoiding the uncontrolled build-up of waste explosives by regular disposal

✓preventing the build-up of explosive dusts, such as on the floors of magazines, through the provision of good housekeeping

✓restricting access to competent operators.

The extent of the management arrangements will depend on the complexity of the operation. A small firm that is simply storing explosives will not need as elaborate arrangements as a large manufacturer will.

Employers must also take appropriate measures to limit the extent of a fire or explosion. This involves:

✓managing stocks of explosives to limit the amount of explosives in areas in which people are likely to be present

✓limiting the number of people in areas where explosives are present

✓keeping explosives away from flammable or combustible materials which could fuel a fire, and away from toxic substances which could be released in the event of a fire.

It may also be necessary to take other steps to contain and safely release the blast effects. At its simplest, this means taking steps to ensure that in the event of a fire, anyone in the immediate area of the explosives can quickly and safely escape. This may include:

✓the establishment of emergency procedures

✓fire precautions

✓fire detection and warning systems

✓means of escape and evacuation

✓fire-fighting equipment

✓measures to protect against explosion

Protecting people

There are several techniques that may be used to protect people in the event of a fire or explosion. The measures to be used should be determined by the risk assessment process and may include some, or all, of the following:

✓the appropriate use of safety screens and barriers

✓remote working

✓personal protective equipment (PPE).

✓Remote working will be the preferred choice in cases where the potential for serious injury or death is significant, including:the manufacture of primary explosives, incorporation of pyrotechnic compositions, mixing and handling of propellants and blasting explosives, medium and large-calibre ammunition shell filling, making detonators.

Safe Disposal of Explosives and Decontaminating damage or deteriorated Explosive.

There are diver approach in selecting the most suitable method of disposal. This should be determined through the risk assessment process. The assessment needs to consider the nature of the explosive and its hazards, the disposal method and hazards created during the disposal process, and the type and position of the disposal site. Anyone disposing of explosives must, so far as is reasonably practicable, ensure that they are disposed of safely. Similarly, those who decontaminate explosive-contaminated items must also ensure, so far as is reasonably practicable, that they are decontaminated safely. The four ways to dispose of, or to destroy, explosives are:

✓burning

✓detonation

✓dissolution or dilution

✓chemical destruction.

Due to environmental concerns, dumping at sea or landfill are no longer considered to be suitable methods of disposal.

Restrictions on the Employment of Young Persons

No one under the age of 18 years should be permitted to work in the manufacture or storage of explosives, except under appropriate supervision. This extends the duties of the Management of Health and Safety at Work Regulations 1999.

Control of Unauthorised Access

ER 2014 places prohibitions on entering an explosives building or area without permission from the licensee or the licensee's representative. The legislation also requires anyone who has entered without permission to leave when requested to do so and permits the occupier to remove the person. It is recommended that the police are called if the person refuses to leave. The occupier should remove unauthorised people themselves only in situations where they consider that there is an imminent threat to the safety of the explosives.

Only reasonable means may be used and these will depend on the severity and imminence of the threat to the explosives. The operator should, normally, make suitable arrangements to mark the boundaries of the site. The decision on whether to erect boundary markers and warning signs will take into account the circumstances of the explosives stored, especially their location. Where further guidance is required, this may be sought from the Police Explosives Liaison Officer.

 IN CONCLUSION,

Storage, usage and Transportation of Explosive from the manufacturer to the magazine or from magazine to the mine site should be done with this safety Tips in place:

1. Never transport high Explosive and other Blasting accessories together

2. Ensure Explosive transportating van is in good condition

3. Ensure the driver is enlighten on what Explosive is capable of doing

4. Check van driver to ensure he is not carrying matches or any flammable material

5. Van wiring parts must be highly insulated

6. Smoking during Explosive transportation is highly prohibited, it can led to the death of thousand

7. Explosive squared and anti bomb security show excort the transportation van

8. Speed limit must be considered for the van as started in Explosive regulation 2014 and others

9. During transportation, Explosive must be store in proper conducive and stable condition

10. Earth electrostatic neutralizer chain must be attached to the van during transportation

11.Ensure all Explosives are properly and formally check in when delivery is made to the magazine.

12. Follow the FIFO (First in, First out) structure when checking out the Explosive in the magazine

13. Proper arrangements should be made for security protection in the magazine

14. Sign indicating danger should be boldly place at the magazine entrance and in strategic positions within the magazine.

15. Precaution tips and symbols should be position in strategic point within the magazine

16. Damage or expired Explosive should be properly dispose by certified Engineers.

17. Misfire Explosive recovered should in no way be placed with other Explosive.

18. Magazine should be barricade by a fence with one entrance.

19. High Explosive must not be store in the same place with other Blasting accessories like cap, booster, safety fuse, detonators.

20. During charging of blast hole, leftover Explosives should be move away from the blast site

21. Exploder should be check properly before use for charge initiation to avoid insufficient release of energy to the charge loop.

22. Explosive charge must not be tamp with iron rods, also during stemming of already connected charge holes is total disastrous.

23. Opening of Explosive cartridge is unsafe

24. Transportation of Explosive with bike or animals I'm an unconducive condition is unsafe.

25.storing Explosive in room, containers or in the mine as the case of many ASM is unsafe

26. All retrieved Explosive from misfire blast should be returned to the magazine for necessary action

27. Boulder sockets from misfire blast should be check properly for undetonated Explosive.

28. Blasting cap and detonators must not be kept in the blastman pocket or take home.

29. If you locate Explosive in any place, report to the nearest police station or Explosive inspectorate in your area

30. Smoking During blast charge or chaining is a death sentence automatically.

31. All unused Explosive must be returned back to the magazine

32. Blast Misfire site must be barricade and abandoned for some time as specified in Explosive regulation and safety Act.

33. During blast hole charging, pulling the Detonation cord or the lead wire in case of electric Blasting is a bad etiquette that can result into misfire

34. Pulling Explosive charge by force or with knife or other metal from misfire holes or boulder socket is a direct call for accident, avoid that

35. Drilling deviated retrieve hole into MISFIRE rock mass is a deadly act and unsafe

36. Standing closer  (<30m) to Blasting site to watch how detonation occur is a direct decision to experience accident.

37. Using a very short safety fuse in a bit to minimize cost is a bad and unsafe act, never try such

38. Improper placement of primer or primer cord into the Explosive before lowering the bottom charge is an easy way to cause blast misfire.

39. High powder factor in secondary blasting is a call for high rate of flyrock, avoid such

40. Positioning Explosive industry near power station, train station and other unsafe location is unsafe

Let all who work with Explosive and other dangerous materials be careful not to subject others into trouble.

Avoid any form of unsafe act and unsafe condition.

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Most prefer reference for this article is ER2014

HOW TO HANDLE BLASTING MISFIRE

MISFIRE DEFINITION

 An explosive charge in a drill hole that has partly or completely failed to explode as planned. Causes include unskilled charging; defective explosive, detonator, or fuse; broken electric circuit or--most dangerous--cutting off of part or all of the charge through lateral rock movement as other holes in the vicinity are fired. Stringent safety precautions cover procedure in minimizing these risks and in dealing with known or suspected misfires. A smoldering fuse may delay explosion, causing a hangfire, so return to workings after a suspected failure is necessary. Another main cause of accident is drilling into or dangerously near a socket--an apparently empty drill hole.

Rules for misfires ( MMMR-2002)

A.When a misfire occurs in a mine, indicated by the counting of exploded shots in case of fuse blasting, or observed by the blaster from other indications in case of electrical or detonating cord blasting, no person shall enter the place of blasting until 30 minutes in case of fuse blasting and 5 minutes in case of electrical or detonating cord blasting after the firing of shots. The place of the misfire shall be marked by a red flag to indicate it as a danger zone.

B. In the event of a misfire, the following procedure shall be followed:

1.The tamping may be sludged out with compressed air or water under pressure and the hole may be reprimed and fired.

2. When the misfire is due to a faulty cable, or is due to a faulty connection in case of electrical firing, the shot may be fired again after the defect has been rectified.

3. Where the steps in Sections 1 and 2 have not been successful, another shot may be fired in a relieving hole where practicable. The relieving hole shall be drilled at least 30 cm away from and parallel to the misfire hole.

4.After the relieving hole has been fired, a careful search shall be made for cartridges and detonators amongst the material brought down by the shot.

5.Before leaving the mine, the blaster shall inform the foreman and the manager of the misfire that has occurred; when a misfired shot has not been relieved or re-blasted, he shall also inform the officer of the next shift before he leaves the mine.

6. The blaster shall record every incident of misfire in a bound-paged book kept for that purpose.

C. The manager shall ensure that utmost care is exercised when working is carried out in the mine in an area where the presence of a misfired hole has been reported and the hole has not been relieved.

HOW TO AVOID MISFIRE

To avoid misfire, the condition of the hole in check for water before loading must be done, proper selection of Explosive and avoid using deteriorated Explosive, careful loading and tamping during stemming to avoid detonating cord damage, proper priming to ensure good placing of the cap into the prime Explosive cartridge.

Defining misfire as

In the case of accidental detonation of Explosive

Precautions include:

1. Proper handling of Explosive during storage and transportation

2. Avoid using low current exploder

3. Stop all Blasting operation under heavy thunderstorms

How to handle misfire when it happens

1. Detect misfire from blast sound and fume observation

2. Give clearance time 15-30mins before visiting the blast area

3. Carryout post Blasting inspection after blasting

4. Demarcate or barricade blast zone with signs after observing misfire

5. Never try to pull out the detonation cord with force from the charge hole

6. Check if the Explosive charge and cord can still be detonated, if yes reblast the charges. If no redrill and recharge the formation with all eye Care. Reblast drill holes should be drill vertically and Abit far from the undetonated hole.

7. Remove any budged or undetonated Explosive and accessories from rock socket to avoid damage to loading , transporting or processing equipments.

Note all undetonated Explosive left over in misfire are unstable, they must be handle with Care.

Life and property must be secured.

Misfire can be classified into three base on cause and source.

 Misfire  resulting from

1. Manufacturer factor

2. Design factor

3. Human factor.

HOW TO DEAL WITH MISFIRE

1. identify type and position of misfire

2. Take remedial action with misfire

3. Recover Explosive material or refire.

STEPS TO DEAL WITH MISFIRE

1.REMOVING STEMMING AND REPRIMING: In doing this, "No use of force".  For electric detonator, do not use high velocity air as it can generate static charge sufficient to initiate the Explosive primer.

For top priming do not forcefully remove Stemming with metal or iron bar. In case of decking, remove inert material from each deck gradually and continuous with care.

For bulk/slurry Explosive, wash off with pressurized water, but for cartridge Explosive, care should be use to avoid unwanted initiation.

Use large quantity of water to desensitize Explosive.

2.DRILLING AND FIRING RELIEVING HOLES

in case of stocked in Explosive charge which I unremovable, instead of using force and create static charge, drilling relieve hole at a define distance from the load Explosive to release the holes is done with precaution.

The relieving hole distance from the undetonated hole depend on the following factors:

a. Diameter of the undetonated hole

b. Inclination of the undetonated hole and that of the Drilling machine

c. Sensitivity of the Explosive in the undetonated hole

All relieving hole must be;

a. Parallel to the undetonated (misfire) hole

b. Be of thesame length with the undetonated hole.

c. Must be lightly charged.

3.DISCOVERY AND RETRIEVAL OF EXPLOSIVE

Most misfire leave Explosive in Muckpile, boulder socket and on bench wall.

Unretrieve Explosive can led to unexpected detonation during loading, haulage or crushing. Therefore, to avoid any unwanted initiation, retrieving all undetonated Explosive cartridge from muckpile help to avoid accident in both mine and milling factory.

Above all steps, post Blasting inspection and blast risk assessment should be done and any evidence of misfire must be handled by expert and competent person.

Misfire zone should be barricade and *All clear* signal should not be given until misfire location is clear.

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DRILLING PRE-PLANNING IMPORTANT

Drilling is the creation of Artificial cavity into rock for the placement of Explosive.

Drilling can be done for different purpose ranging from:

1. Rock Blasting

2. Oil and gas production

3.rock stability and Safety purpose

4. Exploration purpose 

5. Water and borehole drilling

6. Among others.

Drilling for rock Blasting is done for the loading of Explosive into the rock formation so as to generate the shock and gas energy require to fragment the rock mass.

Planning for an event makes the event or operation more perfect and productive.

The condition of the drill holes and arrangements in place of pattern design of the hole drilled for Blasting has great impact on the effectiveness of the blasting.

Some of the parameters that explains the status of blast holes are:

1. Burden: the perpendicular distance between the first drill holes row to the nearest free face. Or in others way, the distance between two adjacent 

Hole rows.this affect distribution of energy within the holes during initiation.

2. Spacing: the distance between two adjacent holes on thesame row.

3. Hole diameter: the circumferential size of the Drilling bit

4. Hole depth: the vertical depth of the drill hole.

5. Hole drill angle, and others

The accuracy of all this drill parameters have great effect on the functionality of the Explosive energy.

To avoid any form of deviation in drill hole angle, error in spacing, burden and other possible mistake we must ensure all planing is perfected, drilling team are aware of the drill plan and purpose, the rock properties and location conditions are studied and account for.

During drilling, the supervisor should ensure drilled holes are checked, count and measured to avoid any form of oversight in depth, design.

Some effect of oversight during drilling:

1. Hole closure with drill cuttings resulting into depth shortage. Depth shortage directly result into reduction in tonnage. The volume of material blasted is a function of hole depth, decrease in hole depth result into decrease in tonnage.

2. Unexpected site Accident: drilling in an unknown geographical so or unknown rock mass formation may result into unexpected accident during drilling. Just as the condition of each rock layers are study during oil and gas drilling to understand the bottom pressure and fluid static condition. Thesame during drilling operation for Blasting, rock been a heterogeneity material it varies in strength and characteristics with depth. Pre-planning before drilling operation proceed will help to avoid any form of drilling Accident. It will also give sufficient information to Blasting team on the required energy needed to fragment the rock mass productively.

3. Poor Blasting output: poor drilling plan (PDP) and poor drilling supervision (PDS) makes blasting team to be stranded of information about the rock formation. Detailed information about the rock mass can best be optained from drill cuttings. Proper supervision of drilling makes the blasting teams to have sufficient information to plan for the blasting operation. The availability of enough information about the rock mass help the blasting team to plan for the charge distribution and density needed to fragment the needed rock mass. It also help blast team to account for possible blast accident. Having understanding of the rock strength, variation in composition, rock structure (dyke,sill among others) help to control charge distribution within the holes column to prevent improper use of charge energy which can result into flyrock, ground vibration among other blasting impact.

In general, drilling operation should be well planed and supervise to avoid any oversight and ensure enough information is provided on the drill log  for blasting team to rely on.

Let Blasting been done safely in accordance to National, global and state laws and regulations.

Say no to illegal mining and use of Explosive and Blasting material as it deadly and bad.

Let Blast safe and relate safely with the ecosystem and earth lithosphere, this is our home.....

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INDUSTRIAL MINERAL MINING: MARBLE

Marble is a white colour calcitic lime stone.

It a stone with  glaring and decorative texture.

It has coarse texture with dominantly calcite Mineral. Marble has white streak but varies in colour from pure white, off white, Ash depending on it formation.It color also depends on the following:

Primary rock from which it formed, composition, degree of weathering process it has undergone, type of metamorphism it undergone (contact or regional) among others. Marble is a monomineralitic rock..

Marble is a carbonate rock, it has hardness of 3 on mohr's scale of hardness.

"Marble More of Formation" 

Marble bus formed through metamorphosim process. When Argillaceous grain limestone undergone metamorphosim under high temperature, it undergone recrystallization which led to the formation of Marble. As existing limestone formation is heat up by intrusive magma it grains undergo Reformation.. Marble is an industrial  rock as it a useful industrial material.

Marble as one of the useful industrial raw material can be mined as aggregate and also can be extracted as dimension block. Marble as a competent rock of compressive strength greater than 35Mpa can be mine by Quarry Mining method, Open pit and other applicable methods depending on the formation orientation, dimension (size&shape), overburden thickness.

Marble aggregate is mine using drilling and blasting to break the marble deposit into handable sizes. 

This method involved the following operation sequentially:

Development operation, Drilling, Blasting, loading and hauling, Processing.

The following documents are required to apply for a Mineral title; Exploration Report, Minimum work program report (MWP) Environmental impact Assessment (EIA), Community Agreement signed by necessary community leaders, evidence of compensation to the land owner and previous land users. Have once explain each of this documents once. In case you want to write or learn how to write you can reach me, I will put you through @Giant Miner training stope.

After acquiring the deposit, development operation start by road creation and land clearing to give a work space allowance where mining can start proper. Development operation: The first thing before any mining operation can commence is to acquire the deposit both as mandated by Mining Act and Regulations. After exploring the deposit, necessary mapping operation to understand formation orientation and dimension is carryout. This is operation is follow by core drilling operation to know both quantity and quality of the formation. All this operation is done under Exploration License (EL). This license is renewable and  can be extend on additional Mineral. After exploration process, Exploration Report is submitted to the ministry of mine office along side with other documents for Mining license processing. After successful Blasting, marble aggregate is load and haul for milling.

Uses of marble aggregate includes; for animal feed production, paint production, cement production, iron ore pyrometallurgical processing in blast furnace, tooth paste and pharmaceutical industrial use, construction purpose, uso as drilling mud addictive among other uses. The marble Run-off-mine is milled into fine product or hammer milled.

After drilling operation which is assumed to be as planned and design in alignment with the mine design.

Blasting operation is done by loading the drill holes with specified quantity of explosive. In open pit the deposit is work in benches, why in Quarry it's worked in a single bench. For the first Blasting operation, box cut Blasting design is use for the creation of additional free face. In the box cut design, inner holes are initiated first then preceeded by the following ones. Th inner hole create a crater which create horizontal Free face. The crater geometry depends on the depth of burial of Explosive and other parameters in place.

Drilling and Blasting operation commence after the deposit has been developed. For both open pit and Quarrying, the overburden material removed from the deposit is stockpile in a remote area where it's kept for reclamation. All operation on this marble deposit must be done as proposed in the minimum work program report (MWP). Drilling as we all know is the creation of cavity into the marble formation for the placement of Explosive. The development operation can b done using Excavator machine, payloader and other mine machineries. Most time when the area to dump marble overburden is far, dump trucks and other haul trucks can be used  Reason why Marble is as useful as it's

Marble compose of calcite (CaCO3). Calcite is a Mineral of high cementric property and it's rich in calcium. Calcite find it use in cement company due to it cementing property and ability to glue. During Diagenesis process of sedimentary rock formations, calcite play the role of cementing sediments together after lithification and dewatering process. This calcite of plane cleavage and two dimensional cleavage plane is said to be formation from the remain of past sea creatures. High calcium content in marble makes it useful for pharmaceutical industry. Marble dimension block Extraction:

Apart from mining marble as aggregate it can be cut into slabs and polish into chair, table and tiles among other things. Marble as a source of calcium is also use for animal feed (pig meal and poultry meal). Marble is use for iron ore process as a reactant to remove hematite (Fe2O3)  oxygen as CaCO3 need more oxide to burn off its carbonate so as to produce quick lime.

When calcite is heated at high temperature, the carbonate content combust and burn off to produce quick lime. When hydrated produce hydrated lime which is a raw material for water purification and other uses. Marble aggregate is useful as an industrial material. 

Marble Dimension block Extraction

Dimension stone Quarrying is another aspect of mining that involves the cutting of rock mass into block which is to be polish into different ornamenal finish goods including chair, table, stool, tiles among other. 

Slab cutting techniques of marble extraction involve creating face for dimension block and detachment of the cut block from the insitu rock. This extraction begins from site mapping to check the formation competency. For a marble formation to be competent for dimension block cutting it must be of; discontinuity and crack free, low water absorption, low porosity, moderate strength among other characteristics. Availability of fracture in rock mass render the formation useless as dimension block material. Existing fractures in marble rock mass (joint, fault, and others fissures) makes it difficult to extract block as they tends to break into chippings and undimensional boulders. High strengtharble formation containing metallic minerals and hard grains affect the cutting tools and it cutting efficiency. Therefore before establishing a dimension block cutting Quarry, the following properties of the formation must be justify with the international Rock Mechanics standard.

Properties to be test for includes but not limited to:

1. Rock Uniaxial compressive strength UCs

2. Porosity

3. Water absorption rate

4. Durability

5. Discontinuity mapping

6. Petrographic check for aesthetic appearance.

7. And others

Marble Dimension stone cutting can be done using cutting machine, drilling and blasting, usebof soundless demolition Chemical Agent and presplitting.

Principle of Control Blasting 1: Presplitting blast Techniques Theory

Open pit mining is one of the surface mining method use in exploiting less overburden material. Open pit method is one of the special mining method use to extract competent ore with flat shape.

This method is unique with it's step wise approach use to mine the deposit in benches.

The safety requirements for the success of this type of mine is not restricted to 

Open pit blasting at first may require box cut approach to create additional free face at the horizontal direction for successful throw.

Mostly if the blasting is carried out at the last bench floor or as the first blasting for face opening.

In such case where:

1. Environmental Impact has to be controlled,

2. Safety of workers, equipment and nearby things have to be presented,

3. Blast economy in place of cost of blasting material effect on overall blasting cost have to be minimize,

4. Success optimum fragmentation size with less than 5% oversize and undersize, and

5. Dilution, overbreak and back break needs to be prevented for high safety and low downstream operation cost sake...

The use of control blasting tends to be very crucial and must be practice in all mine site.

Control blasting is a special Blasting approach that involves strategic control of Explosive energy to avoid damaging intert rock wall and to avoid environmental impact of blasting.

Control blasting techniques include;

1.Presplitting technique, 

2.smooth blasting, 

3.cushion blasting,

4. line drill hole, 

5.post splitting,

 6.Air decking among many others. All control blasting techniques try to achieve the same aim but through different objective.

To control the rate of shock energy, gas energy, radial cracks, flyrock, ground vibration, airblast released during blasting.

But optimizing powder factor, drill and blast design parameters.Thou rock heterogeneity and anisotropic nature makes control blasting design varies from formation to formation.Most civil engineering construction blast involved control blasting to avoid overbreak of wall and floor. Some of the reasons why control blasting is needed:

1. To avoid overbreak: this is creation of discontinuity by the shock energy beyond the bench width during charge detonation.

2. To avoid reduction in support wall strength and competency: fracturing of support wall and toe reduce the stability of slope which prompt rock to easily fall under load redistribution during excavation.

3. To prevent high ground vibration, flyrock, airblast and other environmental Impact 

 4. To control blasting cost through charge weight reduction and still achieve optimum fragmentation

5. To control dilution rate in grade variation formation.

For civil engineering works, control blasting techniques are use to fragment road obstructing rocks (outcrops) during tunneling, building foundation laying and road construction.

This idea is to ensure the hindring rock is break down with competent and smooth face at LHS AND RHS.

Now to presplitting blasting technique after understanding reason why we need control blasting in mining and petroleum (casing perforation at production zone) in civil engineering.

Presplitting is one of the control Blasting techniques use to ensure good Explosive-rock interaction during Blasting. It involves splitting the production zone from the supporting rock block (unblast rock wall). This techniques is differ from post-splitting by the initiation timing as the one detonate production hole first why another detonate perimeter hole First. Presplitting had been practice earlier before the use of Explosive in construction.

In Egypt and other countries, the use of wedge wood and fire heat had be ultilize to split rock mass, likewise in Northern locations spallation effect of freezer water is used. Drill holes are filled with water, as the water frozen it expand and split rock mass.

This traditional approach was used before 1950's. The first presplitting blast wast done in Lewiston power plant as part of Niagera powder project. This was a project involve the blast of dolomite & limestone formation with shale bed.  Many Presplitting method was applied including line hole drilling with three hole step charging, cushion blasting before presplitting was use with dynamite cartridge. The are various type of presplitting:

Traditional, precision and many others but all still in the optimize of Explosive load, stemming and spacing parameters.

From different scholars (Joseph Konya, cook, beckee-kietiakowsky) point of view, Explosive released energy theory were studied to ensure good control during presplitting blast. For the shock wave release, various theory like; Livingston cratering theory, Bureau of mines catering theory, shockwave spallation theory and strain wave theory among others were propanded and infused to ensure the control of micro-fracturing rate during presplitting.

And for the gas energy study for precision splitting, the following equation of state was propanded to calculate the explosion pressure released from charge at detonation; Beckee-kistiakowsky-wilson (BKW) equation of state, Cook's equation of state, Taylor's equation of state, Outoyne-Skidmore-Konya (OSK) equation of state and many more. Learning on the shock and gas energy generation rate during detonation gives the scholar great confidence to give precise and accurate approach to presplitting blast and other Control blasting techniques. If the capacity and energetic strength of each Explosive charge is understand, to control it damage rate becomes easy and accurate.

Presplitting Blast design Parameters

Presplitting make use of the following approach in order to ensure proper Explosive energy;

1. Explosive load weight: blast energy both shock and gas energy increases with exolosive load. During presplitting blast charge, decoupling of peripheral (control holes )to reduce the charge density. Decoupling is the use of small diameter Explosive cartridge in large diameter hole. The decoupling ratio is the ratio of the the Explosive cartridge diameter to the drill hole diameter. Decoupling reduce Explosive energy by creating air allowance between Explosive cartridge and rock wall, therefore the release wave interact with air (having low Sonic velocity) before interacting with the rock mass. In a bit to contain the Explosive energy within the cut line, Explosive load weight is calculated using various design rule of thumb formula including;

Dcc=(Dh^2)/28

Where;

DCC is the charge weight in pounds,

She is the Explosive cartridge diameter.

Also Joseph Konya propose presplitting Konya constant to model Explosive load weight,

K=(40579/E)^0.625

EL=7000*(S/K)^2

Where;

K is the Konya presplitting constant,

E is the rock Young modulus,

EL is the Explosive load weight.

S is the spacing

2. Spacing: spacing is the distance between two adjacent holes in thesame row. Providing wide and optimum space between hole controls the volume of rock block to be fragment by each energy release from each kilogram of edplosive. Increase in spacing reduce the efficiency of hoop stress distribution amongs the holes detonated. The spacing between presplitting holes increase the resistance offer by the rock mass against the release Explosive energy.

Some rule of thumb formula use for spacing during presplitting blast include;

S=10Dh

3. Stemming length: stemming according to konya have no effect on Explosive shock wave but affect the explosion pressure. Well confined holes generate high explosion energy, this will avoid flyrock and also support good throw and backbreak.

4. Initiation timing sequence: Initiation timing of blast charge simple explains the detonation pattern follow by each of the hole during firing. In order for presplitting blast to prevent overbreak at the design boundary between the production block and the supporting rock wall,the peripheral holes (The hole at the production and support wall boundary) are decoupled and initiated first ahead of the production holes. This is where the name Presplitting comes from. The peripheral holes split apart the production section of the ore deposit, creating a free face between the two rock block. This split point avoid further fracturing during production hole Blasting.

Summarize Theory of presplitting blast

The whole idea is to divide the drill hole into two sections.

1. Production holes: holes to be blasted for Run-off- mine crude production Or the holes place in the rich grade zone during dilution control or the hole arranged on the rock mass to be broken away from highway.

2. Peripheral holes or the control holes: These are hole placed at the boundary of the blast rock and supporting wall.

The hole powder factor or load weight is controlled base on the rock strength and the Explosive strength.

Also the hole design is done using specified rule of thumb formula.

The initiation system use in presplitting is design such that the initiating signal reach the peripheral holes first before the production holes. This is achieve through the use of delay detonators (which can be surface delay or down-The-Hole delay). In this case, the charge in peripheral holes are detonated before the production holes charge. The peripheral holes charge is light and decoupled, this ensure perfect splitting and detachment of production block from the insitu rock with smooth face. As soon as the energy from the production hole gets to the split point it's escape to the surface vertically.

Some of the special blasting accessories use for presplitting blast include: delay detonator, decoupling sleeves among others.

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