Introduction

Part 1

Efficient drilling and blasting design is fundamental to achieving optimal rock fragmentation, cost control, and downstream productivity. The first step in designing an effective blast is selecting appropriate geometrical parameters based on rock properties, explosive characteristics, and site-specific conditions. This article introduces initial design ratios that can be used as first approximations in blast planning, keeping in mind that adjustments are necessary as field data is collected.

1. Burden Estimation

The burden is distance between a blasthole and the free face is influenced by rock density and explosive diameter. Initial guidelines suggest:
Light rock (2.2 g/cc): 28 × explosive diameter
Medium rock (2.7 g/cc): 25 × explosive diameter
Dense rock (3.2 g/cc): 23 × explosive diameter
These values can be refined based on fragmentation feedback and in-situ rock behavior.

2. Spacing Between Holes

Spacing ensures uniform energy distribution and reduces overlap or gaps between blast effects:
Instantaneous firing by row: 1.8 – 2.0 × burden
Large-diameter holes (sequential): 1.2 – 1.5 × burden
Small-diameter holes (sequential): 1.15 – 1.8 × burden

3. Bench Height

Bench height depends on operational scale and burden:
Typical range: 1.5 – 4.0 × burden, or higher in some cases.

4. Sub-Drilling

Sub-Drilling ensures complete breakage at the toe, especially important in stratified or dense formations:
Flat bedding at toe: 0.0 – 0.1 × burden
Easy toe: 0.1 – 0.2 × burden
Medium toe: 0.2 – 0.4 × burden
Difficult toe (vertical bedding): 0.5 × burden
General view: (3 to 15) x D

5. Stemming Column Length

Stemming retains explosive energy in the hole and controls flyrock:
General range: 0.5 – 1.3 × burden
Increase multiplier for wet holes or if drill cuttings are used
Decrease multiplier for dry holes or if angular chips are used
For extremely cautious blasting (no throw or flyrock):
Use up to 36 × hole diameter for stemming
Deck delay stemming lengths:
Dry holes: 6 × hole diameter
Wet holes: 12 × hole diameter
Stemming material size = D/10 to D/20

6. Burden Stiffness Ratio (Sr)

=H/B : 2 to 3.5 good fragmentation
 Sr> 3.5 very good fragmentation
Control Blast design
Presplit blasting
Spacing = Hole diameter x 12
Burden = 0.5 x production blast burden (B)
Uncharged length at top = 10 x D
Powder factor = 0.5kg per square metre of face
Smooth Blasting
Spacing = 15 x Hole diameter (hard rock)
20 x Hole diameter (soft rock)
Burden = 1.25 x Spacing
Rock type PF (kg/m3)
Hard 0.7 – 0.8
Medium 0.4 – 0.5
Soft 0.25 – 0.35
Very Soft 0.15 – 0.2

Conclusion

These ratios serve as a starting framework in blast design. Each site’s geological characteristics and performance feedback should guide further optimization. In Part 2, we will explore charge distribution, and initiation to refine blast performance further.
Bibliography
Dyno Nobel Blasting and Explosives Quick Reference Guide 2010
Video credit to Chris Addicott

Understanding the Interaction between Blast Controllable Parameters and Explosive Energy Distribution

Part 2

In surface and underground mining operations, achieving optimal fragmentation and downstream efficiency depends largely on how well explosive energy is distributed throughout the blast zone (Zhang et al., 2023). For drilling and blasting engineers, this distribution is not random, it is directly influenced by the status of controllable blast parameters.

1. Hole Diameter and Burden/Spacing

The size of the blasthole plays a central role in determining the energy per unit volume of rock (powder factor). Larger holes allow for higher explosive loading, but without proper adjustment of burden and spacing, energy may either vent prematurely or be insufficient to break the rock mass effectively. A well-balanced burden and spacing ensures that the explosive energy is confined and directed where it is most effective within the rock’s natural weaknesses.

2. Stemming Length and Type

Stemming acts as a confinement mechanism, and its length determines how much energy is retained to do useful work (fragmentation) versus lost to the atmosphere (airblast and flyrock). Too short a stemming column leads to excessive energy release upwards, reducing breakage efficiency. The stemming material also matters; inert and high-friction materials retain energy better than loose or damp fill.

3. Explosive Type and Density

Different explosives have varying detonation velocities and energy outputs. Choosing an explosive with suitable characteristics for the rock type and desired fragmentation outcome ensures that the energy is neither excessive (leading to fines and overbreak) nor insufficient (resulting in boulders and poor fragmentation). Additionally, the density of the explosive affects how much energy is loaded per unit of borehole length.

4. Initiation Sequence and Timing Delays

The sequence and timing of detonation determine how energy is transferred between holes and how the rock mass reacts dynamically. Proper delay timing ensures effective burden relief and sequential rock movement, promoting efficient energy transfer and reducing the risk of airblast and ground vibration.

Conclusion

Blast controllable parameters are not isolated design factors, they work in concert to shape how explosive energy is distributed and utilized.

Things to Know About WipFrag

WipFrag 4 is a powerful image analysis tool used to assess blast results by evaluating particle size distribution from blast muckpiles images. It helps determine fragmentation quality, boulder presence, and crusher compatibility. With tools like specification envelope, Edit Assist, and autoscale, WipFrag 4 supports continuous blast monitoring and optimization, enhancing productivity and reducing oversize-related costs.
Click QUI to download and learn on the demo for free.

“Blast safely with proper PPE”

The Importance of Bottom Charge and Energy Distribution in Blasting

Part 3

In surface and underground mining operations, achieving optimal fragmentation through effective blast design is key to operational efficiency. One critical yet often underappreciated aspect of blast design is the bottom charge the portion of explosive placed at the bottom of the blast hole and how it contributes to energy distribution within the rock mass.

What is Bottom Charge?

The bottom charge, also known as the column base charge, is typically a higher-density explosive or a concentrated portion of the total charge placed at the toe of the hole. Its main function is to initiate breakage from the bottom up, ensuring that the entire burden is effectively fractured and displaced.

Why It Matters

1. Crushing and Fragmentation at the Toe

The toe region is the most resistant part of the burden. Without adequate energy at the bottom, poor fragmentation or even toe problems (hard toe) may result. A well-calculated bottom charge ensures that this area receives enough energy to initiate crack formation and propagation.

2. Improved Energy Distribution

Uniform energy distribution along the blast hole is vital. Concentrating more energy at the bottom allows better stress wave propagation, reduces energy loss into air gaps or stemming zones, and leads to more consistent fragmentation throughout the burden.

3. Reduction of Fly Rock and Overbreak

A well-designed bottom charge reduces uncontrolled energy release at the top of the hole, minimizing fly rock and overbreak. This promotes safer and cleaner operations, especially in populated or infrastructure-sensitive areas.

A Simple Step-by-Step Calculation for Bottom Charge Quantity

1. Determine the hole diameter
 Let’s assume:
2. Hole diameter d=102 mm=0.102 m
3. Cross-sectional area of the hole (A):
A = (pi*d*d)/4
A= 0.00817m^2
4. Explosive density (ρ): Assuming ANFO ρ=850kg/m^3
5. Determine bottom charge length
Let’s assume:
Bottom charge length (Lb)=1.2 m
6. Calculate the bottom charge (mass)
Bottom charge mass=A×Lb​×ρ=0.00817×1.2×850≈8.33 kg
What determine the bottom charge length?
Rock hardness and strength, Hole diameter, decking strategy, Bench height, Desired fragmentation and toe breakage, Stemming length, Water presence in the hole, Desired throw or displacement, Blast pattern, geometry, etc. The role of the bottom charge goes beyond merely initiating the blast.

WipFrag enables accurate fragmentation analysis from blast images, providing essential data for evaluating blasting effectiveness. It supports continuous improvement by identifying oversize issues, optimizing blast designs, and ensuring crusher compatibility. With real-time feedback and specification envelopes, it enhances decision-making, and improves overall mine-to-mill performance efficiently.
Read a case study paper HERE
Video credits to Goran Petrovic

Introduction

In the field of mineral processing and comminution (crushing and grinding), accurate size analysis is essential for optimizing the performance of crushing circuits and downstream processing units. Effective rock breakage using explosive energy requires a well-optimized blast design to ensure the energy is directed into the rock mass for maximum fragmentation and minimal waste. A properly executed design enhances breakage efficiency, improves downstream processing, and produces consistent material sizes measurable through Particle Size Distribution (PSD), which represents the proportion of different particle sizes within a fragmented material sample. One of the most critical parameters used in particle size distribution (PSD) analysis is P80, which stands for the particle size at which 80% of the sample material passes. This article discusses the definition, importance, and application of P80 in the crushing process and overall mineral processing operations.

What is P80?

P80 refers to the particle size (usually expressed in micrometers or millimeters) at which 80% of the sample’s mass passes through a given screen size. It is derived from the particle size distribution curve and provides a representative measure of the overall coarseness or fineness of a crushed or ground product.

For example:

• If the P80 of a crushed ore is 120 mm, it means that 80% of the mass of that sample will pass through a 100 mm screen.

How is P80 Determined?

P80 is typically determined through:

1. Sieve Analysis: The material is sieved using a stack of screens of decreasing mesh size. The cumulative mass retained is plotted to generate the PSD curve.
2. Automated system: In automated systems like WipFrag 4, Reflex 6, e Solo 6, image-based particle size analysis can generate PSD curves without physical sieving, using photoanalysis techniques.

Importance of P80 in Crushing and Mineral Processing

1. Crusher Design and Operation Control

The efficiency of crushers and grinding mills is largely influenced by the target P80:

• Primary crushers may target a P80 of around 100–150 mm.
• Secondary crushers aim for a P80 of 20–40 mm.
• Grinding mills (ball or SAG mills) often target a P80 of 75–150 µm for mineral liberation.

Setting and monitoring a P80 helps ensure the crushing process delivers the required product size for efficient downstream separation.

2. Grinding Circuit Efficiency

The Bond work index (BWI) is a well-known method used when selecting comminution equipment, to evaluate the grinding efficiency and to calculate the required grinding power (Nikolić et al., 2021). Determining the BWI is part of the design phase of a mining plant and can significantly affect the design costs associated with comminution. Mining comminution processes are the most energy intensive, and also the area with the greatest potential for energy savings. Accurate determination of the BWI is essential for the proper design and estimation of the costs associated with the comminution process.

P80 is critical in the Bond Work Index (BWI) equation:

W=10×Wi×((P80^-0.5)−(F80^-0.5))

Where:

• W is the energy required (kWh/t),
• Wi is the Bond Work Index,
• F80 is the 80% passing size of the feed,
• P80 is the 80% passing size of the product.

This relationship shows how energy input depends on the size reduction from F80 to P80. Thus, optimizing P80 can reduce energy consumption and cost.

3. Liberation and Recovery

In mineral processing, liberation of valuable minerals is essential before separation (e.g., flotation, leaching, magnetic separation).

• If P80 is too coarse, incomplete liberation may occur, reducing recovery.
• If P80 is too fine, overgrinding may lead to slimes that reduce separation efficiency and increase reagent consumption.

An optimal P80 ensures maximum liberation with minimal energy and operating cost.

4. Crusher-Compatibility and Throughput

When processing material through a plant, particularly in multi-stage crushing, each unit must receive appropriately sized feed:

• Oversized material can cause crusher choking or blockages.
• Undersized material may result in under-utilization of capacity.

By targeting a consistent P80:

• You ensure crusher feed compatibility.
• You maintain steady throughput and minimize downtime.

5. Process Control and Optimization

In modern mineral processing plants, real-time monitoring of P80 allows dynamic control:

• Adjusting crusher settings (CSS),
• Managing screen decks or vibrating screen performance,
• Automating grinding media addition in mills.

Image analysis tools likeSolo 6enable on-belt PSD analysis, providing operators with live P80 data for feedback control either before crushing or after crushing.

Factors Influencing P80

Several factors impact the actual P80 of a crushed or ground product:

• Rock hardness and competency
• Crusher/mill type and operating parameters
• Blasting quality and fragmentation
• Screening efficiency
• Ore variability and moisture content

Continuous monitoring and adjustment are crucial for maintaining a consistent P80 under changing conditions.

Typical P80 Targets by Process Stage

Primary Crushing: 100 mm – 250 mm

Secondary Crushing: 20 mm – 80 mm

Tertiary Crushing: 5 mm – 20 mm

SAG Mill Discharge: 1 mm – 3 mm

Ball Mill Product: 75 µm – 150 µm

Flotation Feed: 106 µm – 150 µm

Leach Feed: 50 µm – 100 µm

Conclusion

P80 is one of the most significant performance indicators in crushing and material processing. It serves as a benchmark for:

• Crusher performance evaluation
• Grinding circuit design
• Energy efficiency analysis
• Liberation optimization
• Quality control and process automation

A well-controlled P80 not only improves the economics of mineral processing but also ensures better recovery and operational stability. With the rise of automation and image-based analysis systems, monitoring and optimizing P80 has become more precise and actionable, empowering engineers and operators to make data-driven decisions.

Reference

Nikolić, V., & Trumić, M. (2021). A new approach to the calculation of bond work index for finer samples. Minerals Engineering, 165, 106858.

WipWare Solo 6 Conveyor Belt System Overview

Blasting and fragmentation are critical operations in mining and quarrying, significantly influencing downstream processes such as loading, hauling, and crushing. At the core of successful blasting lies a precise understanding of how energy is distributed through the rock mass. Among the key factors that can drastically affect blast outcomes is drilling deviation, a common but often underestimated issue that alters the intended blast geometry.

The Impact of Drilling Deviation

In an ideal blast design, drill holes are positioned and angled according to a specific pattern to ensure optimal burden spacing, energy distribution, and shock wave interaction. However, drilling deviation, which refers to the unintentional displacement or misalignment of blast holes can disrupt this pattern (Adebayo & Mutandwa, 2015).

When holes deviate, the spacing and burden between them can become inconsistent. This misalignment affects shock wave propagation, leading to uneven energy transfer across the rock mass. In zones where spacing is too wide, the energy dissipates prematurely, resulting in poor rock breakage. Conversely, overly tight spacing can cause excessive energy concentration, increasing the risk of overbreak and flyrock.

These irregularities directly influence rock fracturing. A well-fractured rock mass ensures the production of uniformly sized fragments. But with drilling deviation, fragmentation becomes unpredictable. As a result, the blast may yield a mix of fines, oversize boulders, and inadequate intermediate sizes, which compromise both crusher compatibility and operational efficiency.

Approaches for Calculating Drill Hole Deviation (Manzoor et al., 2022)

Drill hole deviation refers to the departure of a drilled hole from its intended path in terms of length, direction, and angle. Accurate assessment of this deviation is essential in mining and civil engineering projects where the precision of hole placement affects fragmentation, blasting efficiency, and overall project outcomes. There are several practical approaches used to define and evaluate drill hole deviation, particularly focusing on hole length variation, toe deviation, and hole angle.

1. Hole Length Variation Approach

This approach compares the actual drilled hole length to the designed or planned length. In many cases, the planned length is measured from the collar (starting point) to the expected toe (bottom of the hole) along a straight path. Deviations in length often indicate that the drill has wandered off the intended path, especially in steeply inclined or deep holes.

• Shorter holes than planned can suggest upward deviation or bending along the path.
• Longer holes may indicate downward deviation or drilling past the toe due to misalignment or geological inconsistencies.

Monitoring length variation is particularly useful in controlled environments where design lengths are standardized. This method is a straightforward first check to determine if a hole might be deviating and to what extent.

2. Toe Deviation Approach

Toe deviation assesses the horizontal and vertical displacement of the actual hole end point (toe) from its intended or designed location. This is a direct measure of deviation and one of the most reliable indicators of drilling accuracy.

• Toe deviation is typically evaluated using survey tools or borehole tracking systems that pinpoint the actual toe position.
• Displacement in the horizontal plane indicates lateral drift.
• Displacement in the vertical plane can suggest a variation in drilling dip or depth.

Understanding toe deviation is crucial in blast design and mineral exploration, where accurate positioning at the bottom of the hole influences rock breakage efficiency, ore recovery, and safety.

3. Hole Angle Deviation Approach

Angle deviation refers to the difference between the planned drill angle and the actual drilled angle. This can be assessed at various points along the hole but is especially important at the collar and near the toe.

• Even small angle deviations can cause significant offset at the toe in long holes.
• Deviations can occur in both the azimuth (horizontal angle) and the inclination (vertical angle), leading to spiraling or drifting holes.

Angle deviation is commonly tracked using a gyro or borehole camera, and its identification is vital in situations where hole alignment impacts the outcome, such as in perimeter control blasting or directional drilling.

Particle Size Distribution Consequences

Poor fragmentation due to drilling deviation leads to:

• Increased presence of boulders that require secondary breaking.
• Excessive fines that may cause dust problems and reduce haulage efficiency.
• A wider particle size distribution (PSD) curve, indicating inefficient energy usage and poor blast performance.

Recommendation: Using WipFrag for Improvement

To mitigate the effects of drilling deviation and ensure consistent fragmentation, incorporating WipFrag image analysis software into the blast assessment process is highly recommended. WipFrag enables:

• Real-time fragmentation analysis, helping to evaluate PSD curves right after the blast.
• Identification of zones with excessive boulders or fines, linking these to potential drilling inaccuracies.
• Comparison of multiple blast results to detect patterns in performance deviations caused by hole misalignment.

Using WipFrag’s specification envelope tool, engineers can assess if the fragmentation meets crusher compatibility standards and adjust their drilling and blasting parameters accordingly. Furthermore, integrating WipFrag into a continuous improvement cycle ensures better control over drilling precision, energy distribution, and overall blast performance.

Conclusion

Understanding the fundamentals of blasting goes beyond explosive placement, it demands accurate drilling. Drilling deviation disrupts the propagation of shock waves and leads to poor fragmentation, affecting both safety and productivity. Leveraging tools like WipFrag empowers mining professionals to monitor, analyze, and improve blast results, ensuring a more efficient and cost-effective operation.

References

Adebayo, B., & Mutandwa, B. (2015). Correlation of blast-hole deviation and area of block with fragment size and fragmentation cost. International Research Journal of Engineering and Technology (IRJET), 2(7), 402-406.

Manzoor, S., Danielsson, M., Söderström, E., Schunnesson, H., Gustafson, A., Fredriksson, H., & Johansson, D. (2022). Predicting rock fragmentation based on drill monitoring: A case study from Malmberget mine, Sweden. Journal of the Southern African Institute of Mining and Metallurgy, 122(3), 155-165.

Introduction

Blasting is a critical operation in mining, quarrying, and construction that involves the controlled detonation of explosives to break rock into manageable fragments. The fundamental principle behind blasting lies in understanding the interaction between explosive energy and rock mechanics, particularly the propagation of shock waves and the subsequent formation of fractures.

The Shock-Wave Theory of Blasting

The shock-wave theory provides a framework for understanding how explosive energy transforms into mechanical work, breaking the rock. As mentioned by Hino, (1956), when an explosive charge detonates, it generates an intense shock wave accompanied by a rapid release of gas and energy.

This energy produces two primary effects:

1. Crushed Zone Formation:

Near the explosive charge, the rock undergoes intense compressive stress, exceeding its compressive strength. This creates a crushed zone, a region where the rock is pulverized into fine fragments. However, because rocks generally have a high compressive strength, this crushed zone is limited to the immediate vicinity of the charge.

Figure 1 )Shadab Far et al., 2019)

2. Shock Wave Propagation:

Beyond the crushed zone, a high-pressure shock wave propagates outward as a compressive wave. This wave does not immediately cause rock breakage but transfers energy through the rock mass.

At the first free face (a boundary with no external constraint, such as the surface of a bench or tunnel wall), the compressive wave reflects as a tensile wave. In rock mechanics, this transition is crucial because rocks are significantly weaker under tensile stress than under compressive stress. As the tensile wave interacts with the rock, fractures form when the effective tension the difference between the reflected tensile wave and any residual compression exceeds the rock’s tensile strength (Himanshu et al., 2024).

Thickness of the First Slab and Fragmentation

The initial fracture caused by the tensile wave occurs at a distance from the free face known as the thickness of the first slab (Hino, 1956). This distance is critical because:

• It determines the size of the initial fragment.
• Other fragment dimensions are generally proportional to this thickness.

If the remaining compressive wave retains sufficient energy after the detachment of the first slab, it continues propagating outward (See Figure 2). This process repeats at newly created free faces, producing successive layers of fractures and reducing the rock into smaller fragments. The cycle continues until the energy of the compressive wave diminishes below the tensile strength of the rock.

The interaction between these phenomena: shock wave propagation, energy dissipation, and rock strength, governs the fragmentation process. Understanding these principles allows blasting engineers to optimize blast designs to achieve desired fragment sizes, minimize blast induced issues like ground vibration, flyrock, overbreak, and ensure efficient downstream operations.

Factors Affecting Shock-Wave Propagation and Fragmentation

Several factors influence the effectiveness of a blast and the resulting fragmentation:

1. Explosive Properties

• The energy content, detonation velocity, and confinement of explosives significantly affect the shock wave’s intensity and duration.

2. Rock Properties

• Variations in rock strength, density, and structure (e.g., joints, fractures, and bedding planes) influence the propagation of shock and tensile waves.

3. Blast Design Parameters:

• Hole diameter, spacing, burden, and the placement of charges determine the distribution of energy and the resulting fragmentation.

4. Free Face Orientation:

• The presence and orientation of free faces play a pivotal role in enabling tensile wave reflection and fracture initiation.

5. Energy Distribution:

• Proper distribution of explosive energy ensures uniform fragmentation and minimizes the generation of oversize boulders or fines.

Importance of Fragmentation in Mining Operations

Effective fragmentation is essential for the efficiency and cost-effectiveness of mining operations. Well-fragmented rock facilitates:

• Reduced loading and hauling costs.
• Improved crusher throughput and efficiency.
• Lower energy consumption in downstream processing.
• Enhanced safety by minimizing the occurrence of hazardous oversize boulders.

Importance of Assessing Blast Performance and Output

WipFrag, a state-of-the-art image analysis software, revolutionizes the assessment of blast performance and fragmentation. By analyzing images of fragmented rock, WipFrag provides precise and actionable insights into the quality of a blast. Here’s how WipFrag enhances blasting operations:

1. Particle Size distribution (PSD) Analysis:

• WipFrag generates PSD curves that quantify the size range of rock fragments, enabling operators to evaluate whether the fragmentation meets specifications.

2. Specification Envelope Assessment

• The software allows users to define specification envelopes for crusher-compatible fragmentation. Deviations from these envelopes highlight areas for improvement in blast design.

3. Boulder Identification and Counting:

• WipFrag’s advanced algorithms detect and count oversize boulders, providing critical data for optimizing explosive placement and burden.

4. Image Merging and Orthomosaic Integration:

• The capability to merge multiple images ensures comprehensive analysis of large muck piles. Integration with drone orthomosaics enables wide-area assessment of blast results.

5. Continuous Improvement:

• By comparing fragmentation results across blasts, WipFrag supports continuous improvement in blasting practices, reducing costs and improving efficiency.

6. Real-Time Analysis:

• Integration with systems like Solo 6 and Reflex 6 facilitates real-time monitoring and analysis, ensuring immediate feedback for decision-making.

Figure 3

Figure 3 showcases results obtained from the WipFrag software, illustrating its capabilities in fragmentation analysis.

• Figure 3a presents the GIS-integrated on-site fragmentation assessment. This feature, embedded within WipFrag, allows users to visualize blast results spatially. The red sections of the GIS map highlight areas with poor blast outcomes, whereas lighter colors like blue and green represent zones with favorable fragmentation.
• Figure 3c displays the Particle Size Distribution (PSD) curves comparing three different blasts. The yellow envelope outlines the production specification of the case study mine, serving as a benchmark. WipFrag enables each mine to define their Key Performance Indicator (KPI) sizes and utilize them for ongoing assessments. This facilitates the evaluation of blast improvements over successive rounds.
• Additionally, the PSD curves feature size classifications and flag specific sizes that deviate from mine production requirements, ensuring precise monitoring and alignment with operational goals.

This comprehensive analysis provided by WipFrag aids in identifying areas of improvement, optimizing blasting strategies, and enhancing overall mining efficiency.

Conclusion

Blasting and fragmentation are complex processes driven by the interaction of explosive energy, rock mechanics, and blast design parameters. Understanding these fundamentals is essential for optimizing operations and achieving desired outcomes. WipFrag software plays a pivotal role in this optimization by providing detailed and accurate fragmentation analysis, enabling operators to assess performance, identify areas for improvement, and implement data-driven strategies for continuous enhancement. With tools like WipFrag, the mining industry can achieve safer, more efficient, and cost-effective blasting operations (download software here https://wipware.com/get-wipfrag/).

References

Hino, K. (1956). Fragmentation of rock through blasting and shock wave theory of blasting. In ARMA US Rock Mechanics/Geomechanics Symposium (pp. ARMA-56). ARMA.

Himanshu, V. K., Bhagat, N. K., Vishwakarma, A. K., & Mishra, A. K. (2024). Principles and Practices of Rock Blasting. CRC Press.

Shadab Far, M., Wang, Y., & Dallo, Y. A. (2019). Reliability analysis of the induced damage for single-hole rock blasting. Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, 13(1), 82-98.

March Newsletter

Introduction

WipFrag software provides detailed fragmentation analysis through histograms and Particle Size Distribution (PSD) charts. These tools help users assess particle size consistency and shape uniformity, which are critical for optimizing blasting and crushing operations. Two among the key elements in WipFrag analysis are the histogram e il sphericity lines on the PSD chart.

Interpreting the WipFrag Histogram

The histogram in WipFrag displays the frequency of particle sizes within specific bins, helping to visualize fragmentation trends. Here’s how to analyze it:

1. X-Axis (Particle Size Ranges): Represents particle size classes based on the sieve analysis standard.
2. Y-Axis (Frequency or Percentage Passing): Shows the proportion of material in each size class.
3. Histogram Shape:
   • A normal distribution suggests well-balanced fragmentation.
   • A right-skewed distribution indicates excessive fines.
   • A left-skewed distribution suggests large boulders dominate.

By analyzing the histogram, users can determine whether the blast produced the desired fragmentation or if adjustments are needed in blast parameters.

Understanding Sphericity Lines on the PSD Chart

Sphericity represents the ratio of particle length to width, indicating shape uniformity. WipFrag incorporates sphericity lines on the PSD chart to provide insight into particle geometry:

• 100% Sphericity: Indicates perfect uniformity (equal length and width).
• 70-90% Sphericity: Represents well-shaped, near-uniform particles, ideal for crushing and handling.
• Below 70% Sphericity: Suggests elongated or irregularly shaped particles, which may impact flowability and crusher efficiency.

Why Sphericity Matters

• Higher sphericity (>70%) improves material flow and crusher compatibility.
• Lower sphericity (<70%) may cause blockages in crushers and conveyors.
• Well-distributed sphericity values indicate a good mix of particle shapes.

Interpreting WipFrag histogram and sphericity lines helps assess fragmentation quality and shape uniformity. By understanding these parameters, mine operators can fine-tune their blasting strategies for optimal size distribution and material handling efficiency.

Download WipFrag here: https://wipware.com/products/wipfrag-image-analysis-software/

How to Use WipFrag for Blasting Quality Control (QC)

WipFrag, a leading photoanalysis software, enables real-time fragmentation assessment, helping engineers and operators maintain blasting quality control (QC) and improve efficiency.

Step-by-Step Guide to Using WipFrag for Blasting QC

1. Image Capture and Data Collection
   • Capture high-quality images of the blast muck pile using a UAV (drone), camera, or mobile device.
   • Ensure proper lighting and image clarity for accurate particle detection.
   • Use WipFrag’s Auto Scale feature or place a scale reference in the image for precise measurements.
2. Image Processing and Fragmentation Analysis
   • Upload images into WipFrag software.
   • Use the Edit Assist tool to refine particle outlines and improve accuracy.
   • Generate a Particle Size Distribution (PSD) curve to analyze the fragmentation results.
3. Assessing Fragmentation with Histograms and PSD Charts
   • Histogram Analysis: Identify particle size frequency and distribution trends.
   • Specification Envelope: Compare fragmentation results with the desired range for crusher compatibility.
   • Sphericity Lines: Assess shape uniformity to ensure good material flow.
4. Boulder Identification and Oversize Control
   • Utilize WipFrag’s Boulder Count tool to detect and quantify oversize particles.
   • Identify areas where secondary breakage or blasting adjustments are needed.
5. Continuous Improvement and Optimizaton
   • Compare multiple blasts using WipFrag’s Merging Feature to track fragmentation trends.
   • Adjust blasting parameters (e.g., burden, spacing, explosive charge) based on data insights.
   • Improve fragmentation efficiency by reducing fines and oversized materials.

Conclusion

WipFrag is a powerful tool for Blasting QC, enabling operators to measure, analyze, and optimize fragmentation performance. By integrating WipFrag into the blasting workflow, mining professionals can achieve better consistency, reduce operational costs, and enhance overall efficiency.

We’ve put together some photoanalysis systems FAQs based on questions from our customers.

For more information about our systems, please visit our YouTube channel.