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.