In underground mine blasting, the location of the initiation hole and reamer holes is crucial for achieving efficient and safe blasting results. Here are the key reasons why their placement is important:

Optimizing Fragmentation:
The initiation hole, often referred to as the blasthole, is typically drilled at a strategic location within the rock mass to achieve optimal fragmentation. The goal is to break the rock into smaller, manageable pieces that can be easily handled and processed.
Reamer holes are additional holes drilled around the initiation hole to enhance the fragmentation pattern. The proper placement of reamer holes helps in breaking the rock mass more uniformly and reducing oversize rocks.

Controlling Rock Movement:
Initiating the blast at a specific location helps control the direction of rock movement. This is important for safety and to prevent damage to underground infrastructure or equipment.
Reamer holes can be strategically placed to direct the force of the blast in a controlled manner, reducing the risk of flyrock and ensuring that the energy is utilized efficiently for breaking the rock.

Minimizing Vibration and Overbreak:
Proper placement of blastholes helps in minimizing ground vibration, which is important to prevent damage to surrounding structures, tunnels, and workings. Controlling the location and timing of the blast helps achieve the desired results while minimizing undesirable side effects.
Reamer holes can also be used to control overbreak, which refers to the unintended fracturing or displacement of rock beyond the desired excavation limits. By placing reamer holes strategically, miners can reduce overbreak and maintain the integrity of the surrounding rock mass.

Ensuring Safety:
Careful planning of blasthole and reamer hole locations is crucial for the safety of personnel working in the underground mine. This includes avoiding the creation of unstable rock conditions, controlling the release of gases, and preventing the occurrence of hazardous situations such as rockfalls.

Efficient Ore Recovery:
Properly placed blastholes contribute to efficient ore recovery by facilitating the extraction of valuable minerals in a way that minimizes dilution and maximizes the yield of ore.

In summary, the careful consideration of blasthole and reamer hole locations is essential for achieving effective fragmentation, controlling rock movement, minimizing vibration and overbreak, ensuring safety, and optimizing ore recovery in underground mine blasting operations.

⭐Designing surface mining blasts involves a thorough understanding of the geological, geotechnical, and environmental factors.

⭕Geological Assessment:
◽Identify rock types, their hardness, and structural features.
◽Consider the presence of any natural fractures, faults, or weaknesses.

⭕Blasthole Design:
◽ Determine the optimal drill hole pattern and spacing.
◽ Drill hole diameter and depth should match the rock characteristics and desired fragmentation.
◽ Ensure proper burden (distance between blastholes) and spacing ratios.

⭕Explosive Selection:
◽ Choose explosives based on rock type, density, and desired fragmentation.
◽ Consider environmental impact and regulatory compliance.

⭕Initiation System:
◽Select an initiation system that ensures proper sequencing and timing of explosions.
◽Electronic initiation systems allow precise control over blast timing.

⭕Blast Design Software:
◽ Utilize specialized software for blast design to simulate and optimize blast outcomes.
◽Consideration of vibration, air blast, and flyrock limits is crucial.

⭕Vibration Control:
◽Monitor and control ground vibration to prevent damage to nearby structures.
◽Adjust blast parameters to minimize vibration levels.

⭕Flyrock Mitigation:
◽ Implement measures to control and minimize flyrock, which can pose safety hazards.
◽Use blast mats or berms to contain and redirect flyrock.

⭕Air Blast Control:
◽ Control air blast levels to prevent damage to structures and ensure compliance with regulations.
◽Adjust blast parameters and distances accordingly.

⭕Safety Measures:
◽ Implement strict safety protocols for personnel involved in the blasting process.
◽ Ensure a secure blast area, and use warning systems to alert workers.

⭕Environmental Impact:
◽ Minimize dust generation through water spraying or other dust suppression methods.
◽ Comply with environmental regulations and consider the impact on air and water quality.

⭕Monitoring and Evaluation:
◽Continuously monitor and evaluate blast performance.
◽Adjust future blasts based on lessons learned and changes in geological conditions.

Source: Karim El-behairy, LinkedIn

The Australian Centre for Geomechanics has developed this safety training video for underground metalliferous mine workers.

Overview
All underground mine workers will be exposed to drilling and blasting processes. The aim of this video is to provide workers with the critical knowledge on drilling and blasting to aid appreciation of the importance of these mining processes and their related hazards. The video features an introduction to the rock breaking process in mining, followed by a section on how to handle, store and transport explosive products. The third part of the video covers development drilling and blasting practices; and the fourth part discusses production drilling and blasting.

Target Audience
Underground mine workers – the need to identify the potential hazards of working near or with explosives, and the protocols of re-entering a working area after blasting.
Workers responsible for development and production drilling and blasting activities. This video will review drilling and blasting fundamental concepts that are critical to achieving optimal rock breaking outcomes.

All industry stakeholders – those keen to learn more about drilling and blasting in underground mines.

Project Sponsors: Barrick Gold of Australia; BHP Billiton Olympic Dam; Dyno Nobel Asia Pacific; Gold Fields Australasia; Newmont Asia Pacific; Orica Mining Services; Xstrata Zinc.

Credits: Australian Centre for Geomechanics

Blast optimization

Luego de haber realizado la voladura de rocas, realizarás el levantamiento topográfico para luego calcular el volumen preciso del tajeo. Puedes importar la información de topografía al software RecMin y proceder al cálculo de volumen con cualquiera de los métodos de cálculo que posee el software y obtener resultados precisos, esto puede servir para calcular los costos de transporte por metro cúbico o volumen o saber la cantidad de mineral enviado a planta o a desmonte. El software es gratuito y la herramienta de cálculo de volumen también. EL software está en español y sirve muy bien para el control de este tipo de operación. Ve y descarga RecMin y úsalo de forma gratuita para apoyo a tus trabajos.

Source: Dyno Nobel, YouTube

TBT introduced at the ISEE in Denver 2020 conference the first full 3D realistic blast simulation.

A major step in blast simulation that allows everyone to predict the outcome of a blast (mouvement, fragmentation, vibration, dilution and overbreak) with few minutes of computation.

The video shows the vibrations of the blast shaking the pit while the blast mouvement happened.
Color coding of the small blocks shows fragmentation or dilution.

Available to anyone who doesn’t want to be surprised when pressing the trigger…

Source: I-Blast software – ISEE – Thierry Bernard, YouTube

What blasting looks like up close ?
A selection of our four favorite close-up blast videos from the last year – which one is your favorite?

Note: “Favorite” does not necessarily mean that it was a good blast and rather refers to the “visual appeal”. But be careful of judging blast quality too quickly. The perspective of close-up filming distorts your perception by heaps.

Source: ERG Industrial, YouTube

Hoy en día existen métodos para analizar los daños colaterales producidos por la voladura, tal es así que el uso de equipos como los sismógrafos que son aplicados mayormente para el control de los limites permisibles de vibración en construcciones superficiales es adaptado para realizar análisis de vibración en condiciones subterráneas (Minas) y establecer parámetros que permitan un mejor diseño de excavaciones en avances y producción.

Bajo este preámbulo podemos afirmar que hoy en día en la mayoría de las veces se diseñan mallas de perforación y Voladura sin conocer parámetros límites tan importantes como la Velocidad Critica de Partícula de la Roca (Vcrit) de acuerdo a la clasificación Geomecanica y la Carga Operante Máxima (Q’) que es la cantidad máxima de explosivo a detonar. Bajo ese escenario es imposible contrastar lo resultados obtenidos para el diseño contra lo que admite o resiste el MACIZO ROCOSO .

Es en ese sentido que propongo una nueva forme de diseño en el orden que se muestra en la diapositiva (Forma inversa a lo tradicional).

Fuente: Amilcar Carpio Chavez, LinkedIn
Si quieres mas información al respecto, lo encontraras en mi libro titulado: ” DISEÑO DE SOSTENIMIENTO EN MINAS SUBTERRANEAS”
Contactos al WhatsApp +51 986371646

La minería subterránea por lo general tiene un menor impacto ambiental, pero también implica mayores costos. Por eso, hoy quiero compartir con ustedes una valiosa herramienta: la plantilla de barrenación de avance para mina subterránea. 👇

Esta plantilla permite realizar análisis rápidos de costos de explosivos, determinar el material volado y planificar los materiales necesarios. Puedes llevar a cabo simulaciones de diferentes escenarios y elegir aquel que te beneficie más, yra sea mediante la reducción de la cantidad de barrenos, el ancho u otras variables relevantes.

Pronto, compartiré información sobre cómo diseñar una cuña.

Source: RUBEN ROBLES R., LinkedIm