Open pit mine design: Key to optimize productivity

Short ways reduce open pit mine operation cost:

1. Proper design: remember proper preparation prevent poor performance (5p's  key of good operation system). When it comes to open pit mining I always like to make mine plan and Design first as the key ways to optimize and garantee profitability.

See through this: The following factors are the dictator of stripping ratio (Stripping cost), Drilling and Blasting, loading and haulage operation, then processing operation.

Find the factors below and how that affects the about operation:

Factor number 1: Bench height: This is the maximum vertical extension of the mine bench also define as the vertical distance from the toe to crest of a bench. This factor determine the type of loading equipment that will be strictly permit in the mine for loading because, the loading boom of the equipment must not be longer than the bench height. Small loading equipment means low production or high cost of getting enough loading equipment that will fit for your production target as shown by your fleet design.

It also affect dilution control in the mine, heigh bench height result into large hole Drilling, and large powder factor which may result in external dilution through overbreak, internal dilution through backbreak. It also affect selective loading. All which increase production cost by increasing haulage cost (more waste move to Processing plant), increase mine life (by reducing recovery mill efficiency) and also reduce ore grade automatically reducing ore market value.

Get other factors explain in my blog @ giantminer.blogspot.com

THE SAFE BLASTING AND THE CONTROL BLASTING PRINCIPLE

LEARN ON BLASTING PRINCIPLE AND MECHANICS BEHIND CONTROL BLASTING

INTRODUCTION

From the view of Hoek brown failure graph and failure criterion equation adjustments using the Geological structural index GSI, variation is confirmed to occur in the rock strength parameters due to the effect of Blasting, this was shown in the addition of Rock disturbance factor D to the determination of s,mb and a which are the rock factors constant.

Rock is known to be DIANE (Disvontinous, Anisotropic, Heterogenous and non elastic) according to various claim by rock mechanist like N. Barton among others.

Since rock has such dynamic characteristics, it becomes very difficult to understand the perfect behavior of Explosive energy and the quantity of powder require to cause the breaking and the casting of the rock mass. 

Actually what the  generated during blast need to reflect is change in medium (solid to air, solid to liquid), this is the important of free face. Free face is the region of Freedom or escape of wave from one medium to another. face reflect the traveling wave and cause it to be effective for fracturing.

Check my videos on rock breakage and article on it. For the full content you will enjoy it and understand why Explosive Perform splitting at wall when using control Techniques like presplitting, post splitting, cushion Blasting, empty hole line Blasting. In line hole Blasting, the uncharged holes create Free face to reflect back traveling wave, prevent fracturing and make gas energy in active for explosion at the unmined region.

The presplitting principle also use this, from Konya work in 1980s he develop a constant that explains the charge weight needed to perform the splitting base on the rock strength and the hole spacing.

Actual splitting principle

What happened during splitting is that, the wall boundary is fractured ahead of the main Blasting, therefore creating a wave barrier region which prevent the traveling of the shock wave into the bench face. Actually from Examine 2D software checking, as a Boundary element Method of Numerical design approach for  excavation, the induced stresses at the competent zone of any excavation is low due to the Excavation damage Zone which show a residual stress behavior, from this claim, I come to understand that, the wall of a presplitting mine has low induce stress which contain low stress concentration, and due to this create a change medium for shock wave reflection back to the main Blasting area.

Just as the free face assist in reflecting the shock wave to perform full tensile slabbing in normal Blasting operation, so did the split area does in presplitting region.

Reason for Control Blasting

Mining is a field concern with the use of appreciate method and Technology which support both the safety of the mine and the profitability of the project. Therefore to achieve this and prevent any form of barriers like, rock wall fall, wedge sliding, overbreak beyond design stole width, ground vibration, air blast, rock Burst due to suddenly release of stored strain energy in tensioned rock, noise generation beyond 80-85dB (A), prevention of Fly rock from mine face to safety zone/region among others.

The place of Control Blasting can not be overlooked if a mine will like to work the ore profitably, poor fragmentation result into truck idle time during load, low machine ultilization factor there is the ultilization factor is greater than unity, dilution both internal and external, poor fragmentation with low uniformity index among others.

When the Blasting result is poo, it makes the process operation poor also, it affect all downstream operation from crushing to grinding, to Libration to separation of concentrate from the waste, more cost will be incur on Transportation and more cost in processing and storage..

In Conclusion, Control Blasting operation give assurance of safety and profit. The major problem something lies in the supervision and design of the blast which brings about variation in blast result compare to the expected design work. The bottleneck in Blasting operation is not just the Explosive energy but the pre-planning stage which requires proper plan and operational stage out for good Blast. Above all, Safety is the first goal, let all Blasting operation be done in a safe and secure manner, proper coordination of Explosive handling, ensure the queue discipline of First come first serve (FCFS) Or First in First out (FIFO) is adopted in the magazine to prevent Explosive been deteriorated or expired by passing the shelf life. All unused Explosive materials must be moved from the site before firing, the maximum instantaneous charge must be use to determine the best safety distance to position mine machine to avoid damage due to fly rocks and debris, for the NONEL Blasters, ensure the safety fuse is properly insert and tighten in the cap, never use stone or try use teeth to tighten cap cylinder to the safety fuse, avoid using short length Safety fuse, let the length factor of Safety be at Least Greater than 2.5, do not because of cost, overcut the fuse, all electric Blasting operation must be suspended during cloudy or lightening, test the exploder before using it, Check the current Available and that required to initiate the blast, check the connection using appropriate equipment to avoid current breakage within row or inter row, ensure in hole charges are properly tap and properly steamed with the steam length needed.

Finally, Blasting is a control and safe bombing that is for production, when is produce unsafe and hazardous impacts it becomes disastrous, likewise having Explosive in the wrong hand is a threatening to humanity and the nation, no unauthorized person is expected to be in possession of Explosive and Explosive materials not even the cartoon or a cut of fuse (Explosive Acts).

Therefore, detest from the stealing of Explosive materials from site to sell illegal, it I a criminal offense and punishable under the Explosive and mining Act. Let all mine manager  see to the welfare of there employee to avoid such act and unsafe act.

All activities in the mine must be a team work, let the workers be motivated by providing both financial and non financial motivator for them.

You can learn on:

Abraham Maslow's motivation theory,

Herzberg two factor motivation theory,

McGregor Theory X and Theory Y for employee motivation and finally the carrot and stick approach to avoid negligence in work..

The better the leadership of the minig operation, the good the output result. Set a control measure and performance standard for all blasting operation and supervise the Control both open and close free reins.

Mining operation is the best way to keep humanity alive and kicking, we produce the material for all production, no mining no cars, no manufacturing, no innovation.

Let mine the earth safely.

About the writer:

Giant Miner is a fresh graduate of Federal University of Technology Akure, He graduate from the department of Mining Engineering and Engineering Technology.

He is ready for internship in any mining company and wish to contribute to any mining operation both in Nigeria and outside Nigeria.

Reach Giant Miner on:

WhatsApp contact:+2347031018600

BLASTING AND EXPLOSIVE PROPER USE: A view on Oxygen balance

INTRODUCTION

Operations in mining industry is mainly effected by the mine work because more cost is involved and safety is required.

 Blasthole Drilling shows the creation of holes into the rock mass for the placement of Explosive with the intention of fragmentation. According to Barry, (2016) liberation process begin from the mine. Though libration occur in two ways, the intra granular and inter granular libration, both occur during Blasting and during comminution.

All Mining Engineering is concern about is extracting the ore from the earth crust safely and getting it to the beneficiary plant for processing, in a bit to achieve this we have the earth stress field been Disturbed and the safety of men been questioned as the various activities in Mining affect both the biosphere and the Abiosohere. This article discuss the process of Blasting as a key way to getting the rock insitu fragmented and the place of safety Paramount as far as profit is concerned. The article also centered on ways to prevent misfire and other blast related impact. 

Blasting operation in view

During Blasting operation, the Explosive wave travels within the rock mass and create stress redistribution within the intact mass rock. At the concentration region the rock fails toward the free face under crushing, at the relaxation zone within the elastic and plastic region, it fails under shearing and tension slabbing. The definition of Blasting becomes complete when the job is done safely. When Explosive is use for industrial purpose and Explosion is achieved successfully without any injury or hazard, with good production, such then is define as a good Blasting. What really makes Blasting dangerous is not the Explosive to say, but the Explosion energy generated from the Explosive at Detonation. 

Basically during the interface between initiating energy and the Explosive charge, two energy is generated,

1.Shock wave (Energy)

2. Gas energy

By CJ model explanation from the above image, two pressure is defined to exist, the explosion pressure and the Detonation pressure. The Detonation pressure is the pressure at the CJ plane usually calculate by the expression below

P=0.25*De*VD^2

Where , De is the Explosive density in kg/m2, VD is the velocity of Detonation in m/s, p is the Detonation pressure in Kpa. The explosion pressure is the pressure generate behind the CJ plane at the disintegration process of the Explosive, it is half of the Detonation pressure. It grows incrementally to shock wave and gas Energy which Perform micro-fracturing and Explosion (rock movement).

 Explosive can burn or deflagrate if enough shock Energy is not available to start the exothermic reaction within the Explosive chemical composition. Deflagrated Explosive is when it burns gradually with gas energy and toxic gases release from it. I will be partially worried if I don't talk about the issue of oxygen balance and it effects. 

Oxygen balance is the balance of gases generated from Explosive at Detonation such that  nontoxic gases are generate from the Explosive and only environmental fumes like oxygen, carbon IV oxides are those release at complete Detonation. There are three type of oxygen balance, zero OB, negative OB and positive OB. Zero OB is when the Explosive at Detonation release enough oxygen require to react with compound and elements like Nitrogen, carbon and hydrogen to form nontoxic gases like water vapor, Co2 e.t.c

Positive oxygen balance is when the Explosive at Detonation release excess oxygen which is sufficient to neutralize or react with elements like Nitrogen, hydrogen, carbon to for nontoxic gases and fume.

Negative Oxygen balance when the Explosive at Detonation release insufficient oxygen content for the neutrality of toxic gases. Such situation support generation of Co, NOx e.tc which are toxic and irritant to human, plant and general ecosystem.

 This makes the issue of proper supervision and Orientation of mine workers handling and using Explosive imperative, all Explosive manufacturers have designed the Explosive product to be a balance oxygen Explosive, therefore the addition of other Explosive components to add to Detonation result affects the Explosive oxygen balance and can also lead to Explosive deflagration (burning with low or zero shock wave). Explosive can be widely classified into two basically, 

1. Industrial Explosive

2. Military Explosive.

 The industrial Explosive are those use for mine Blasting and construction blast works. They are designed for peace and not for war!! Many try to ask the basic different between the military Explosive and the Industrial Explosive. Actually the major difference is that, the military Explosive contain high percentage of primary (high) Explosive like Trinitrotoluene (TNT), Nitroglycerin Among others which are highly sensitive and release high amplitude shock wave that travels faster than the speed of sound.

Components I industrial Explosive

 Industrial Explosive are basically made with the following components, oxider, retarder, stabilizer, combustive and Energy material like charcoal e.t.c

This components are add together at different proportion which increase in one can affect the other.

Note: As a mine Engineer, poor use of Explosive is when you try to blend or add other compound or material to Explosive during charge time to increase it output. Some may work but most will affect the Explosive oxygen balance, leading to the release of brown-pink color gas indicating Nitrogenous gas compound. Never should you add anything to the Explosive to avoid change in composition and Explosive constitutes at decomposition point behind the CJ plane. 

Also, misfire which is the incomplete Detonation of Explosive, play high key role in release of toxic gases to the environment, the incomplete decomposition of Explosive chemical before the fire cut will affect the complete release of oxygen from Explosive compound for the neutrality of Nitrogen, carbon and other elements preventing the generation of toxic gases.Avoid misfire by checking holes before charging, use FIFO (First in, first out) in Explosive magazine to avoid expired Explosive, stop all charge operation at cloudy or about to rain time.  Check all electric connect well with necessary device before exploder is switched on, check exploder current sufficiency, check all surface connection and timing to avoid cut in sequence wave traveling, in hole connection should be done with precaution and avoid cord damage, tapping should be done professional, do not pull cartridge Explosive with the lead wire during charging process, ensure proper priming, among others.

Contribution to Blast result improvement and M2M efficiency

Benefit of good Blasting

A good fragmentation is that which gives good size distribution and casting, low environmental impact generation such as flyrock, ground vibration and others, strong and smooth wall and toe face, ease and fast loading. Major the Blasting Damage zone (BDZ) is the region with low strength at the bench face, such zone fails easily under dynamic load such as movement of trucks, drilling and impacting, Blasting must be carefully carry out to ensure that excavation face have high strength to withstand the newly induced stress. 

Let all blasting operation be carryout successfully in such that company smiles and all workers rejoice... Say no to Explosive mishandling, say no to manage of safety fuse, say no to poor Explosive transportation scheme, say no to poor Explosive storage, let all magazine be build to standard and let all personnel understand the concept of SAFETY FIRST.. Explosive is for peace and not for war.. It for industrial use and not for war.. let the use of Explosive not be a problem to human, plant, and biosphere in general.. release of aerosol will affect the ozone layer, cause global warming, support acid rain and acid mine drainage.. let say no to ecosystem damage, let the tectonic plate be stable for us all.

We mine it for the people's use and for the safety of the biosphere.... All workers must return home safely and have the night meal in happiness with their families...

We work in team as a Miner!!!!

®Giant Miner

A final year student of Federal University of Technology Akure Nigeria

Mining Engineering department

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FEAR KILLS ZEAL AND ABILITY

NO MORE FEAR: EXAM IS FOR ASSESSMENT AND NOT TO BE FEARED (with testimony)

BY: GIANT MINER

Is there anything to fear than GOD? NO, not even the fear of exam!

Fear is a great barrier to many students and not only affect them emotionally but also close the door of mind to remember things in exam.

Human soul is made of three compactments, 

The mind (room of knowledge)

The Emotion

The will (Decision divider) all connected.

Fear makes student fail because they loss access to their mind which is the base of information for breaking the barrier of examination and test.

If you never experienced it you won't understand, every student wants to have good grade, 98% is fully prepared but not all will finally actualize their expectation this is a fact!

Fear is one of the cloud of limitation when sitting for examination, you may even be prepared but still you have that mind that the question may likely not be from what you have read all over night, imagine!

Fear is a system that kills Christian's Faith, it shut the door of believe and damage the consciousness of God's possibilities available for man.

Fear had exist from the beginning even the fear from disobedient on Adam and Eve after eating the fruit.

But we have not receive the spirit of fear but that of sound mind whereby we cry Abba Father..

I myself was always a victim of fear on many of my exam days this is not limit to even professors.

But later I understand that this so  called fear is a brick mould in sequence even from the first day you print out your course form.

I sometimes feel worried after checking my course load for the semester. The mind of human being is sensitive and have ability to conceive both positive and negative thoughts.

You won't break this brick until you have the mind of christ... 

Ways to conquer fear

We human has an inbuilt fear of failure and criticism naturally.

There are many ways to bury fear of failure which is the base source of  examination fear. Even though not all students like education but no body wants to fail!!

The very first way to overcome the fear of examination is by engaging the holy spirit in your academics.

The holy Spirit is the helper given to us by our creator to help us in all things both spiritual, academical and in all things.

The Lord want us to glorify him in our academics Matt 5:13-16, Isaiah 60:1-2, you have sometime in you that will make you soar above the cloud of fear.

THE HOLY SPIRIT is our senior partner, he is our teacher, he is the thought of our lecturers and he can easily reveal their mind to us.

Many believers never believe the fact that the holy Spirit speaks and can be called upon to Assist in anything even academics.

You have the auction from above you know all things that was apostle Paul confession in 1John 2:20.

It takes faith to recieve this fact, the spirit of God is in us, this same spirit dwells in all men and even those in different countries.

The extent to which you manifest the spirit is the limit to which you can enjoy his full assistance.

Many times fear comes on us in exam Hall  as a result of lack of knowledge about the question.

I submit to you that if you know all the questions ask you will be as bold as a lion and even hear the sound of joy within you as you behold the question.

During 2021 academic Sunday in CACCF fellowship I was to answer this great question about fear, I was so much caught up that I gave the summary of why fear comes in one's mind during exams and test as lack of preparation.

This is the fact, you lack knowledge about the exam question because you haven't effectively and efficiently prepared for the exam. There is different between doing things right and doing the right thing.

Your inability to prepare may be as a result of time factor or lack of access to information both which can be helped by the holy Spirit.

The gift of revelation is the skill manifest by a man through the help of the holy Spirit. The gift belongs to him and he choose to manifest it if we want him to for the glory of God.

This gift of revelation is in three dimension (1 cor: 12)

1. Gift of word of knowledge: The holy spirit through this give you sufficient information to study, to prepare and to explore your handout.

2. Gift of word of wisdom: The holy spirit through this help you to understand the direction to get the best of the course, how to put things when answering the questions, direction to studying among others. 

3. Gift of discernment: You through this enjoy a picture of how the question looks like, what you will be asked, where you will be examined among others.

With the information, direction and discernment data, you don't have to fear anything but just relax and boldly make JESUS proud in your academics.

Many don't have the spirit because they are not yet born again, many have it but they don't engage him, we are limited by what the holy Spirit is capable of doing even in our academics.

As a worker in the vineyard of God someone may have short time to study truly because of fellowship activities which must be First (matt6:33),  but you overcome fear when the spirit gives you all you need, you have the easiest access to the holy spirit help than everyone anytime you use your time for GOD, the holy spirit is the one to optimize your time for you and make you recover all for greater glory.

God knows we will surely need to overcome fear, he surely knows we will need help in our academics that is why we have the person of the holy Spirit to help.

The holy spirit is not a story to talk about, he is real, you speak to him and he will speak to you.

But you can't engage him when you don't even know him, when you are not even a son, when you don't even believe Jesus the source and the finisher of our faith.

The first thing to overcome fear is to get the holy Spirit and you can access him by becoming the son of God. And how can someone become the son of GOD? through acknowledging your sin, confessing them, ask for forgiveness with believe that Jesus Christ had come and had died for us all that we should no longer be a slave to sin. Confess Jesus as you Lord and savior.

With this done, talk to the holy Spirit which is the inheritance of salvation (Ephesians 1) and he will respond to you. You sustain him through the fruit of the spirit, and feeding on the bread of life.

My part which I must not forsake: Preparation

Finally, the holy Spirit is not a magician you have your part to play by preparing. Proper preparation prevent poor performance (5ps' of shift).

You have to be diligent in studying, you must study strategically and consistently.

Be committed and be consistent

The holy Spirit will never engage in zero preparation, he will give you the address, the direction, the energy and the best way to get there you do the traveling.

If you travel less you get less if you travel far you get the fattest. What ever you sow you will reap.

But that little, he will always multiply it for you at all time.

Trust in the Lord and conclude not on your own underhandling, in all your ways acknowledge him and he will direct your path (academic, reading, writing) proverb 3:5-6

Testimony About the Holy spirit

 

I was to write a test one day thou I have prepared fully as the Lord was so faithful to me, on getting to the hall there was a question which is so strange and I wasn't able to decode it.

Then I stopped and pray shortly asking the holy Spirit to help me, then he responded and said start from those you can do, when you get to the one you don't know I will take over. Truly when I got to the unknown question, he takes over and solved it for me in a miraculous way. I was so confused even after the test that when the script came out I was the only one who answered it correctly.

The miracle there is that, when I checked through the answer, it wasn't my strategy of solving question, it was a total approach differ from my statics and sense of thinking.

The holy spirit kills fear and help our weakness.

We are sons of God and not slave, we have access to Dominion through the spirit of God in us.

The Lord bless you in Jesus name

SUBDRILL AN IMPORTANT PARAMETER IN BLASTING

 

SUBDRILL: AN IMPORTANT PARAMETER IN BLASTING

BACKGROUND OF THE ARTICLE

To a non mining Engineer or Blasting Engineer, the question must have come to you most time that, 

1. why subdrill in Blasting, what is the important?

2. Why most subdrill be included in of rock blast and which formation will subdrill not required?

This article provides brief answers to the above knowledge gap.

1. INTRODUCTION

Subdrill by definition is the additional hole length included to the Bench height to improve Blasting result and Bench safety. Most drillhole blasted in the mine especially in small scale miners and artisanal blasting Operation don't include subdrill because they tend not to know it important.

As I have define earlier, there is a specified bench height design to mine an orebody, but the extended hole length beyond the bench height is known as subdrill length. Subdrill is one of the most important Blasting parameters that is use to improve not just the fragmentation rate at the bench toe but also to enhance safety by producing a stable and smooth bench floor and toe.

What are the important of subdrill in Blasting?

The following are the major important of subdrill in blast design:

1. subdrill improve fragmentation at the bench floor

2.subdrill assist the blaster in planing for next blast operation.

3. It aid the mine slope from failing.

4. Subdrill produce a smooth and reliable new bench floor during blasting.

As I have explained in my previous video on Explosive and Rock Interaction part 1&2 and in my journal publication on effect of charge distribution on fragmentation (Taiwo, 2022), I explained that the efficiency of rock fragmentation depends on; powder weight, Burden distance which are few but the major factor that determines the rate of micro-fracturing in rock before explosion. Explosive release shock Energy for fracturing and gas Energy.

The efficiency and performance of the gas Energy depends on the fracturing rate during shock energy distribution according to Sushil Bhandari (1997). The fracturing rate is maximum at tensile slabbing because rock is weak in tensile than in compression (check Ash&Konya,1978 work)

At the toe of a mine bench, the tensile strength of the rock or ore deposit is high due to small or no free face available. This reduce the efficiency of Explosive shock an gas Energy at the toe resulting into poor fragmentation and rough floor. Most time the oversize and boulders are formed from the bench toe, in other cases like underground mine you have put out with sockets in Boulders. 

You have boulder and sockets (hollow cavity) in rocks due to pull out of Explosive charge because the Explosive released shock wave Energy is lower than the rock intact Strength at the toe level. What about this! at the point of Detonation, the shock wave fracture by compression at the crushing zone round the hole collar because the Explosive compressive strength is high at initiation point, the wave further fracture by shearing due to rock Anisotropic and heterogenous nature then fracture by tensioning through tensile slabbing using change in medium impledence and Sonic Velocity. At the bench toe, the rock is intact at all dimension, there's less weak zone.

The Explosive energy is also weak and exhausted, because the primer charge or bottom charge make use of it release energy to initiate the column charge and also perform fracturing, this makes the toe fragmentation becomes difficult and in efficient. Also, note that, the base charge is initiate first and the energy only split without complete tensile slabbing because of unavailability of free face for shock wave reflection, this makes the bench toe yield poor fragmentation.

With this, subdrill provide additional charge length, Explosive charge weight at the bench toe to overcome the high tensile strength. It confirmed that the longer the drill hole the higher the powder factor, the higher the blast powder factor, the higher the Explosive energy (shock and gas) release at Detonation. Having subdrill help to provide sufficient energy which is ultilize to intoxicate initiation and also gear up tensioning time at the CJ plane to ensure completion of wave reflection within hole cracks before explosion and casting time of the insitu rock. Other important of subdrill in Blasting is that, subdrill help to ensure smooth and stable bench floor.

subdrill also ensure the production plan and schedule per blast is achieved.As a Mining Engineer we have plan and Target per blast, our mill and beneficiary plant must operate Continuous non stop, therefore all fleet operation had been planned with several target production per day. If for example 50holes are blasted and we expect 100Tonnes of material, and According to our plan, three haul trucks is needed with one loader to ensure 20 trips per day. Which is expected to keep the mill working for days. Assuming the blast failed at the toe, Producing oversize material, and only 60Tonnes are loadable. This will not only affect operation plan it will also affect operation cost. More diesel will be waste on selective loading, haul truck will be underused, plant will also operate in efficiently.

Subdrill is important, it makes the bench floor smooth and good for Tyre mounted trucks ploughing, in most case after Blasting a need for leveling and surveying to ensure pit is accessible for haul trucks, this becomes additional cost and stress. Subdrill will not just solve this challenge it will improve Blasting fragmentation.

 Is subdrill needed for all type of rock formations?

No, not all formation requires subdrill.

Bedded sedimentary formation Like limestone among others don't require subdrill because of there stratigraphy.strata or layered formation response positively to bottom charge energy because if the weakeness status of the beds. The bed tend to shift under low Explosive Energy because the shock wave will propagate along the cleavage plane (weak plane) of the formation and improve fracturing at the bench toe. Also, the bedding nature of the rock will support creation of smooth bench floor after Blasting.

 In conclusion, bedded formation will support high tensile slabbing with low Explosive Energy. This makes subdrill unimportant.

"How to design subdrill length for a typical Blasting operation" Subdrill is calculate according to rule of thumb as 0.3*Burden distance.

For Langford research work he proposed 0.3*Maximum Burden distance. Subdrill can also be calculated using drill bit diameter using 7.5*D. Subdrill increase charge length by 15.8%. subdrill is important and most be use to optimize Blasting result.

Blast it safely and profitably, all workers and blasters working on the mine site must return home safely to have a happy dinner with their families.. say no to all unsafe Blasting act and conditions...

® Giant Miner

CHECK, VERIFY AND ENSURE IS SAFE: MINING OPERATION PROFIT METER IS NOT MONEY IS SAFETY

IF SAFE AND PRODUCTIVE IS MINABLE

Explosive charge can vary from rock to rock due to the different in discontinuity property, rock Strength, rock impedance, rock type, rock grains packing and other non controllable factors.

Make a good pre-planning before Blasting and also use test Blasting to build a standard blast design for your mine. SAFTEY and Profit must be balance.

Our miners must return home to their children and wife safely. We mine the ore and keep the earth healthy for the next generation.

As you resume to morning, evening and afternoon shift take note of the possible hazards in the mine due to previous operation. Check the mine face in case of overbreak, check the ramp in case of slabbing effect, check blast pile for undetonated Explosive charge, cord, check drilled hole dimension and accuracy, check the operation Condition of your equipment. Check records from last shift person, try and look into any recommendations and complain in the Reports to put them in order. Understand the production target for the day, Design the blast that will produce the target in a good fragment, plan on need items to make the blast and mine run safely and efficiently. 

Reach out to your team, be concerned about their welfarism, get your team into action as a team player, start mining with prayer and end with thanks giving. What we do is simple, liberate the ore from the host rock, load the material into a haul truck, stock pile the run off mine at the processing plant.but more than this, we check for consequences of every operation, carryout job safety analysis JSA, adjust blast controllable factors to sweet and blend the uncontrollable factors. Work with the design slope angle to avoid increase in stripping ratio,and to ensure safety in place of slope face stability. Mining is just a profession you will like to involve in, let the firing Begins 

 As you extract and exploit the earth, check the health of the lithosphere also, treat any form of weaken rock stability Malaria, every possible slope discontinuity daylight fever in the rock face, every typhoid in the continuity of intact rocks must be treated with perfect design. Some need to be eliminated, suspended, isolated, control with Engineering design, administration policy of avoid high risk level on workers through the use of safety PPE. Let understanding be available for all your workers, let all Engineering design be with optimum factor of safety and let all policy, rules and regulations be fully enforced by concern supervisor and Mine managers.  In most mine oversight is the disease consuming their profitability, managers should be involved and carry along in all operation. Blasting most not be done without the *ALL CLEAR* order from the blast coordinator or Blasting Engineer. Let all blasting time be consistent and made known to all workers, let all alarm be sound at least three times before the blast and then after the blast. Working equipments should be trekked away from blast zone do not use them as shield to hold flyrock. Get the machine to a safe place, let all Explosive be use without additional combustive material. Don't do this to increase Explosive Energy it affect the Explosive design OXYGEN BALANCE. 

 Have an emergency response team, and incident Management plan to handle any form of mine emergency, let all policy be in place and visible to all workers. Where Blasting is carried out in unstable temperature or pressure condition proper Explosive and Blasting accessories selection must be done and adjustment must be done to blast design to suit the Working condition. Let all holes be checked properly for in filterated edge water before charging, using ANFO swelled or dissolved in water result in the release of Carbon monoxide fume or other notorious gases with brownish or pale brown color which is toxic and irritants great source of harm to human lungs and health generally. Let mining be a safe Mining and blast be a safe and productive mining. Blast fragment should contain less than 5%undersize and oversize material to ensure smooth run-in of processing plant as planned. Plan ahead of raining season also, design your dewatering system and make it clear to bear your producing capacity. Disappointing buyer is a sign of demolition in market and a sign of reduction in mine revenue. Raining season is know to be a time of low production due to limited access to the mine and low efficiency in productivity, poor pit accessibility, small working space, low haulage operation, unstable mine face due to increase in material bulk density, high rate of misfire. Plan ahead, work ahead and work safely.

Let you mine be safe and let you workers be secured, make environmental health and safety garantee for community, release of dust, ground vibration and high decibel noise during your Blasting and other operations will add to the people's problem, likewise projection of rock debris can break human skull and tear brain appart, it can also break door, crash cars and even amputate body part avoid over charging of hole and control your fly rock. We must make peace with nature to make peace with men, control the rate of ozone layer depletion, reduce rate of green house gases release into the atmosphere. Let make mining work out, if the material is not mine, then it is grown. Industry feed on us let production rate increase to reduce poverty rate through production of materials, employment, source of income to people, infrastructural development, social economy growth among others. Mining Engineer is a profession and not a hand skill, let all company be managed by competent person, supported by as many as needed assistance to make things work.

Be safe and make the mine safe.. Follow my page, read my blog articles @ giantminer.blogspot.com

 ® Giant Miner

HOW TO MINIMIZE MINE OPERATION COST WITH DRILLING AND BLASTING OPTIMIZATION

HOW CAN OPERATING COSTS IN SURFACE MINING BR REDUCE THROUGH DRILLING AND BLASTING OPERATION

 This article is divided into the following subtopics:

1. What is mine operation cost?

2. Key factors that affect operation cost

3. Drilling and Blasting operation influence on operation cost.

4. How to optimize drilling and Blasting to minimize operation cost.

BRIEF ON MINE OPERATION COST

 As a Mining Engineer working in a mine, we are all concerned about safety first then profit and constant cash inflow.

It obvious that, if their is no profit then there is crisis as this will be a tunnel to salary payment delay and even lost of our company customers.

"As continuity is the code of Continuous demanding"

MINE OPERATION COST: This is define as the total cost incur to produce a unit ton of an ore from the earth crust.

OPERATION COST IS DIVIDED INTO THREE

1. LABOUR COST

2. RAW MATERIAL COST

3. MISCELLANEOUS COST

1.Labour cost is the cost incur to compensate human effort as contribution to material production in the mine.

2. Raw material cost is the operation cost that includes all expenses incur to ensure all operation unit in the mine is operating efficiently. This includes diesel bought for loader, trucks, ANFO mixing, Tyre and equipments maintenance costs among others

3. miscellaneous cost are other cost put in place to ensure operation in the mine run smoothly and at high efficient rate. Thou may not be constant but are usually use to optimize productivity such as transport expenses from mine to city, food bought for labourer as compensation and to energies them. Having define and explain what mine Operation cost mean, I will like to submit to my readers that, this operation cost can be affected by various factors, various operating conditions.Miscellaneous cost is also known as overhead cost in economists term.

This is the money use

For other activities during production to enhance operation efficiency.

This can include the  bonus given to worker due to extraordinary job done, money for recharge card to mobilize workers to the site among others)

It not usually constant per day or per ton of Run-off-mine produce per day.

Even though during the short run of any mine it understood that operation cost per ton of ore production is usually high why at long-run it usually low.

>>Then why do operation cost increase at the shortrun (start up stage) of a mine and reduce at the long-run (future stable stage) of a mine?

Let me quickly differentiate between operation cost and operating cost..

Operation cost is the total money budgeted to carryout an operation in the mine.

Why

Operating cost is the actual cost or money incur to ensure that an operation is successfully executed or carryout.

As a Mining Engineer planing to produce say 50Tons per day at a projected operation cost of $1 per Ton there is possiblity of poor Blasting reducing the production rate for days or possibility of water infiltration into the pit from aquifer or surface water inflow which may require dewatering operation, then increasing operation cost per ton to say $1.5 per ton.

The budgeted operation cost is $1 but the operating costs is $1.5

 Mine project has two basic stages of production, technically and generally:

Short run stage and long run stage.

The short run stage is the starting point of a newly open mine. In this short run stage, the operation cost is usually very high and the mine is known to be at loss margin, most case low or no profit because operation cost is very high.

This is because various operations that dictates the operation cost amount are usually very capital consuming and of poor result.

what are the operations that factors and affect mine operation cost??

Professionally, a typical mine have 5 operation life cycle and each of this cycle influence the operation cost of the mine per day, per shift, monthly and yearly.

These operation cycles are:

1. Development operation.

2. Drilling operation,

3. Blasting operation.

4. Loading operation and

5. haulage operation

These five operations are carryout in a cyclic sequence through out the life of a typical mine.

You develop the deposit, drill holes into the formation, load the holes with exolosive, blast the hole to produce rock fragments, load the muckpile into dump truck, Transport or haul it to the processing plant.

Then development for a new drilling and blasting starts again....

This is why it is a cyclic operation and Continuous through out the mine life until the ultimate pit life is reached.

The five operations at short-run are usually capital intensive.

To start a new surface  mine say open pit mine.

The cost of stripping the overburden at the beginning is so high and capital intensive compare to other developmental Operation including pit maintaining cost after every Blasting.

Likewise the first Blasting operation may produce high dilution rate due to intrusion or overburden caving or overbreak due to unavailability of mine face at the first Blasting.

The important of free face in Blasting control and efficiency is so important that we can't just bypass it, even if not sufficient we use box cut to create new at the rock mass center.

Likewise in case of a mine at short run, the first Blasting is called the face creation Blasting, it not usually productive, it includes more of external dilution. This and many other reasons makes a typical Quarry or mine to have low profit at short run stage.

Time won't permit I will have talk on haulage also, the ramp for the first bench is not usually of imperfect gradient, the fleet Design plan may likely not even work at the starting point of the mine it takes time to get the best design to make haulage work in a new mine.

You have more trucks queueing, sometimes the loader or excavator may need to separate the muckpile, select material base on size and even dilution control purpose by this under using the dump truck operation time.

 Now, for long-run stage all the mine face had be created, the fleet Design formula had been perfected, good ramp gradient had been ultilize to efficiently transport run-off-mine to the mill, good blast Design had been Design with rule of thumb to avoid overbreak, external and internal dilution so time waste in selective loading can be minimized.

This is why, operating cost is usually low at long-run compare to short-run stage of any mine.

Since I have mentioned the basic operation factors affecting the variation of operation cost in the mine, i will dip into:-

 How Drilling and Blasting operation affect Operation cost and how to optimize this operation to minimize operation cost.

It is not new to us as an engineer that rock is a combination of various Mineral and Mineral is a combination of various elements. This characteristic makes rock very Anisotropic (not having constant Strength all over) and heterogenous (not uniform both in composition and in physical and chemical property).

Also, we understand from scholars research that rock expecially the igneous and metamorphic are of high Uniaxial compressive strength due to their thermogenesis and metagenesis origination.

And we as a Mining Engineer, we befriend rock mass to win the ore (occurrence of Mineral accumulation with economic use).

To win this ore we need to librate the rock mass so we can convey only the concentrate (valuable) material to the Mineral processing plant for comminution (crushing and grinding operation) and Separation process.

As a Blasting Engineer we aim at using the best Explosive quantity to break down the rock mass into transportable sizes which requires less loading and milling operation.

When a Blasting Engineer failed to produce good fragmentation it automatically increase the mine operation cost.

This is very serious and imperative unlike other operations, drilling and Blasting don't just increase the mine operation cost but also increase the milling and mineral processing cost.

Starting from drilling operation and it's effect on Blasting and then on operation cost...

Selection of small drill hole diameter reduce the Burden and spacing of Drillholes, it reduces the Drilling depth and then increase the number of drill hole per Blasting.

Let me prove this shortly using Langford or rule of thumb formula to design a blast with two different hole diameters.

Considering two Blasting:

Hole 1: diameter is 0.004m (jack hammer drill machine)

Hole 2: diameter is 0.065m (say wagon drillhole)

For hole 1: 

Using rule of thumb

Burden (B)=25-45*hole diameter (using 30*d)

B=30*0.04

Burden=1.2m

Spacing=1.15*B (staggered pattern)

S=1.15*1.2

S=1.38m

For hole 2: 

Using rule of thumb

Burden (B)=25-45*hole diameter (using 30*d)

B=30*0.065

Burden=1.95m

Spacing=1.15*B (staggered pattern)

S=1.15*1.95

S=2.24m

Assuming we are to Blast a bench of 25m by 25m

The implementation of this two holes diameter is that,

For  hole 1, more hole will be drill on the bench Why for hole two, less holes will be drilled:

Let proof that also

For hole 1

Number of hole per column (Nc)= bench area÷Bench

Nc =(25m*25m)/1.2

Nc=625/1.2

Nc=521holes

Numbers of holes let row on the bench (Nr)=Bench area/spacing

Nr= 625/1.38

Nr=453holes per row

Total holes to be drill is Nr*Nc

Total hole= 236,013 holes.

 For hole 2

Number of hole per column (Nc)= bench area÷Bench

Nc =(25m*25m)/1.95

Nc=625/1.95

Nc=321holes per column

Numbers of holes let row on the bench (Nr)=Bench area/spacing

Nr= 625/2.24

Nr=279holes per row

Total holes to be drill is Nr*Nc

Total hole= 89,559 holes.

The implementation is that the diameter affect both spacing and burden, it affect the number of holes drilled.

Imagine a different of 146,454holes between the two hole diameter.

More hole means more working days to carryout Drilling operation, more working days implies more diesel consumption per day, more operator allowance per day, more equipment cost per day..

This affect operation cost directly without any measure.

Drilling accuracy of drillhole collar and column also affect the efficiency of Blasting, it create problem in the stope after Blasting.

Poor drilling accuracy affect the distribution of Explosive Energy withing the hole thereby resulting into 

1.poor fragmentation

2. Generation of flyrock

3. Overbreak

4. Ground vibration and others

1.Poor fragmentation increase operation cost by prolonging loading time. Loading time prolonged result into decrease in production per day.

Less material will be move from the mine to the mill.

More diesel will be waste as the loader tries to separate oversize boulders to load optimum size.

2.Generation of flyrock can cause damage to equipment, house and even break someone's head leading to total close down of the mine. Damage to equipment will cost more money, why breaking of someone's head or causing injury can cost the company weeks of no work or total closure of the mine which can be open after payment of compensation and diver fine if license is not withdraw from mine operator.

3.Overbreak directly weakens the bench wall and may lead to plane or wedge failure. Sliding down of rock mass on workers will be a disastrous senario, also closure of pit will cost high development cost, you know high cost of equipment for loading sand and debris, high cost of moving waste out of the mine...

4. Likewise ground vibration distabilies structure, cause disturbance to nearby fellows which can lead to submission of petition against your company...

Also, if the mine site location is closed to the earth tectonic plate edge region possibility is that earthquake may surface or land subsidence...

Drilling and Blasting operation really affect operation cost a lot.

Beyond that it affect milling and process cost for both metallic and non metallic Minerals.

 Poor Blasting is define by me as that which generate environmental illness like airblast, ground vibration, flyrock among others and that Blasting which produce  poor fragmentation with poor loading processing efficiency.

When a Blasting is confirmed to be a poor Blasting, it increases overbreak, increase dilution rate and also subject other downstream operations into chaos.

In case of metallic ore, production of external dilution due to overbreak and internal dilution due to backbreak not only cause a delay in loading and increase in mine operation cost, it also increase the cost of milling, increase the cost of separating the gangue (waste materials, barren rocks, host rocks) from the run-off-mine.

This not only affect the operation cost it gradually increase the mine life, it affect the mine capital payback period, reduce the company productivity Net present value.

Payback period is the schedule time for a mine or any business to return the initial investments back and begin to make profit.

 Net present value NPV is a project Profit analysis tool use to compare the present value of the initial capital cost of a project to the present value of the cash inflow.

Having more diluted run-off-mine affect the profit margin of a mine beyond just affecting operation cost 

So as a mining and Blasting Engineer we need to hold our position well and plan well to ensure we deliver a good blast that will not just be safe but also profitable to load, transport and Mill to process.

It confirmed that initiation pattern with poor timing will also create problem to blast result,

Likewise poor burden distance, poor stemming length, poor Explosive selection among others.

Having  misfire is also another problem that will affect operation cost of a mine.

How can drilling and Blasting be optimize  to minimize operation cost?

I have answered this question in my words above indirectly.

But I will stretch my time to give clear rib support and crown pillar support to the answer  (Don't mind I just go underground to borrow terminology)

To Carry out a good Blasting, there are three things you need to know and implement:

1.Proper Blast Pre-planning 

2. In charge planing

3. Post Blasting planing

1.Pre-planning include:

 a.understanding the Rock material

b. Mapping of rock formations to understand the discontinuity condition

c.selection of best blast Design and blast parameters (hole diameter, burden, spacing, Stemming length, bottom charge length and weight, column charge length and charge weight, powder factor e.t.c) all this are very important.

d. Selection of best Explosive with the sufficient property to function at the blast location

e.selection of best drilling machine Among others

Taking a sharp look at powder factor:

 it is the economic control loop for Blasting operation, it determine the quantity of explosive you will use and the cost to fragment a ton of the ore.

If powder factor is high that implies that more Explosive will be purchase, operation cost will increase.

If powder factor is low, poor fragmentation is certain, increase in loading cost and haulage cost.

All this parameters must be optimzed and balance.

If burden distance is large, poor fragmentation is certain, as this dictates the rate of tensile slabbing at the Explosion CJ plane. If burden distance is to much the shock wave will not complete micro-fracturing before the gas Energy is release meaning more of oversize material will be produced..

 All the parameters are important, as blast Engineer we should consider balancing them with the uncontrollable factor of the rock (Uniaxial compressive strength, rock elasticity, discontinuity nature, and rock geotechnical properties)

2.In charge planing:

This is an action control measure.

There are basically three key elements of production optimization and safety garantee in a mine.

1. Engineering level: This involves blast design and preparation.

2. Education: this includes educating and training personnel on how to implement the blast Design on site to provide the expected result.

3. Enforcement: human will always be human as we are not machine, you need to supervise workers to ensure complete and correct implication of Design.

No oversight supervision, no unsafe act supervision.

All Blasting operation stages are well monitored and supervise by competent Engineer..

If poor Stemming length or material is used, you have pull out and other poor result from Blasting operation.

If workers decided to steal Explosive and Blasting accessories then use low quantity material due to your absence on site, this is directly going to affect Blasting output an increase production cost

 Finally, the post Blasting plan include checking out the blast result and making proper plan and recommendation for next Blast operation.

In conclusion:

As a Mining Engineer or mine  company CEO reading this article, the best way to minimize operation cost is to plan, implement and supervise the implementation on site.

Blasting is for safety and not for damage.

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