Methods of Drivages in Underground Metal Mining

I. Introduction

A. Importance of Methods of Drivages in Underground Metal Mining

Methods of drivages play a crucial role in underground metal mining operations. These methods involve the excavation of tunnels, shafts, and raises to access and extract valuable mineral deposits. The selection of appropriate drivage methods is essential for ensuring the safety of miners, optimizing production efficiency, and minimizing costs.

B. Fundamentals of Methods of Drivages

1. Definition of Methods of Drivages

Methods of drivages refer to the techniques and processes used to create underground openings in metal mines. These openings provide access to ore bodies, facilitate the transportation of personnel and equipment, and enable the extraction of minerals.

1. Role of Methods of Drivages in Underground Metal Mining

Methods of drivages are integral to the overall mining process. They serve the following purposes:

• Accessing ore bodies: Drivages provide entry points to reach the mineral deposits located underground.
• Ventilation and air circulation: Drivages help maintain a safe and healthy working environment by facilitating the flow of fresh air and removing harmful gases.
• Transporting personnel and equipment: Drivages serve as pathways for transporting miners, machinery, and supplies to different areas of the mine.
• Evacuation routes: In case of emergencies, drivages provide escape routes for miners to exit the mine safely.

1. Various Unit Operations Involved in Methods of Drivages

Methods of drivages involve several unit operations, including:

• Drilling: The process of creating holes in the rock using drilling equipment.
• Blasting: The controlled use of explosives to break the rock and create openings.
• Excavation: The removal of broken rock and debris from the drivage using machinery.
• Support and reinforcement: The installation of support systems, such as rock bolts and shotcrete, to ensure the stability of the drivage.

II. Raise Boring

A. Definition and Explanation of Raise Boring

Raise boring is a method of drivage that involves the excavation of vertical or inclined shafts, known as raises, from one level to another within an underground mine. This method is commonly used for ventilation, hoisting, and access purposes.

B. Key Concepts and Principles of Raise Boring

1. Raise Boring Equipment and Tools

Raise boring requires specialized equipment and tools, including:

• Raise boring machines: These machines are designed to drill and enlarge the pilot hole in a controlled manner.
• Reaming heads: Reaming heads are used to enlarge the pilot hole to the desired diameter.
• Casing or liner: A casing or liner is installed in the raise to provide structural support and prevent collapse.

1. Process of Raise Boring

The raise boring process involves the following steps:

• Preparing the drilling site: The drilling site is prepared by clearing the area and ensuring proper ventilation.
• Setting up the raise boring machine: The raise boring machine is positioned and anchored securely.
• Drilling the pilot hole: The machine drills a small-diameter pilot hole from the lower level to the upper level.
• Enlarging the hole using reaming heads: Reaming heads are attached to the machine to enlarge the pilot hole to the desired diameter.
• Installing the casing or liner: A casing or liner is inserted into the raise to provide stability and prevent collapse.
• Completing the raise: The raise is completed by removing the raise boring machine and connecting the upper and lower levels.

1. Safety Considerations in Raise Boring

Safety is of utmost importance in raise boring operations. Some key safety considerations include:

• Proper training and certification of operators
• Regular inspection and maintenance of equipment
• Implementation of safety protocols and procedures

C. Step-by-step Walkthrough of Raise Boring Process

1. Preparing the drilling site

Before starting the raise boring process, the drilling site needs to be prepared. This involves clearing the area of any obstructions, ensuring proper ventilation, and setting up safety barriers.

1. Setting up the raise boring machine

Once the drilling site is prepared, the raise boring machine is positioned and anchored securely. The machine is aligned with the planned trajectory of the raise.

1. Drilling the pilot hole

The raise boring machine starts drilling a small-diameter pilot hole from the lower level to the upper level. The drilling process is carefully monitored to ensure the hole is drilled accurately.

1. Enlarging the hole using reaming heads

After the pilot hole is drilled, reaming heads are attached to the raise boring machine. These heads gradually enlarge the hole to the desired diameter. The process is controlled to ensure the stability of the surrounding rock.

1. Installing the casing or liner

Once the desired diameter is achieved, a casing or liner is inserted into the raise. This provides structural support and prevents collapse. The casing or liner is typically made of steel or concrete.

1. Completing the raise

After the casing or liner is installed, the raise boring machine is removed from the raise. The upper and lower levels are connected, allowing for the flow of personnel, equipment, and materials.

D. Real-world Applications and Examples of Raise Boring in Underground Metal Mining

Raise boring has various applications in underground metal mining, including:

• Ventilation shafts: Raise boring is commonly used to create ventilation shafts that ensure the circulation of fresh air in the mine.
• Ore passes: Raise boring can be used to construct ore passes, which are vertical or inclined chutes used for transferring ore from one level to another.
• Service raises: Raise boring is employed to create service raises that provide access for maintenance, repairs, and installation of utilities.

E. Advantages and Disadvantages of Raise Boring

Raise boring offers several advantages, such as:

• Increased safety: Raise boring eliminates the need for blasting, reducing the risk of accidents and injuries.
• Precise drilling: Raise boring allows for accurate drilling, ensuring the desired trajectory and diameter of the raise.
• Cost-effective: Raise boring can be more cost-effective compared to conventional drilling and blasting methods.

However, there are also some disadvantages to consider:

• Limited to vertical or inclined raises: Raise boring is not suitable for creating horizontal tunnels or drifts.
• Equipment limitations: Raise boring requires specialized equipment, which may not be readily available or suitable for all mining operations.

III. Tunnel Boring

A. Definition and Explanation of Tunnel Boring

Tunnel boring is a method of drivage that involves the excavation of horizontal tunnels, known as drifts, in underground metal mines. This method is commonly used for transportation, access, and exploration purposes.

B. Key Concepts and Principles of Tunnel Boring

1. Tunnel Boring Equipment and Tools

Tunnel boring requires specialized equipment and tools, including:

• Tunnel boring machines (TBMs): These machines are designed to excavate tunnels by cutting through the rock.
• Cutting head: The cutting head is the front part of the TBM that contains the cutting tools.
• Conveyor system: A conveyor system is used to remove the excavated material from the tunnel.

1. Process of Tunnel Boring

The tunnel boring process involves the following steps:

• Preparing the tunneling site: The tunneling site is prepared by clearing the area, ensuring proper ventilation, and setting up support systems.
• Setting up the tunnel boring machine: The tunnel boring machine is positioned and anchored securely. The cutting head is aligned with the planned tunnel trajectory.
• Excavating the tunnel using the cutting head: The tunnel boring machine starts excavating the tunnel by rotating the cutting head and applying pressure to the rock.
• Removing the excavated material: The excavated material is transported out of the tunnel using a conveyor system or other means.
• Installing the tunnel lining: Once the tunnel is excavated, a lining is installed to provide structural support and prevent collapse. The lining may consist of concrete segments or other materials.
• Advancing the tunnel: The tunnel boring machine continues to advance, repeating the excavation and lining installation process until the desired length of the tunnel is reached.

1. Safety Considerations in Tunnel Boring

Safety is paramount in tunnel boring operations. Some key safety considerations include:

• Proper training and certification of operators
• Regular inspection and maintenance of equipment
• Monitoring of ground conditions and stability

C. Step-by-step Walkthrough of Tunnel Boring Process

1. Preparing the tunneling site

Before starting the tunnel boring process, the tunneling site needs to be prepared. This involves clearing the area, ensuring proper ventilation, and setting up support systems such as rock bolts and shotcrete.

1. Setting up the tunnel boring machine

Once the tunneling site is prepared, the tunnel boring machine is positioned and anchored securely. The machine is aligned with the planned trajectory of the tunnel.

1. Excavating the tunnel using the cutting head

The tunnel boring machine starts excavating the tunnel by rotating the cutting head and applying pressure to the rock. The cutting tools on the head break the rock into smaller pieces, which are then removed from the tunnel.

1. Removing the excavated material

The excavated material is transported out of the tunnel using a conveyor system or other means. This ensures that the tunnel remains clear for the machine to continue its excavation.

1. Installing the tunnel lining

Once the tunnel is excavated, a lining is installed to provide structural support and prevent collapse. The lining may consist of precast concrete segments that are placed sequentially to form a ring.

1. Advancing the tunnel

After the lining is installed, the tunnel boring machine continues to advance, repeating the excavation and lining installation process. This allows for the continuous construction of the tunnel.

D. Real-world Applications and Examples of Tunnel Boring in Underground Metal Mining

Tunnel boring has various applications in underground metal mining, including:

• Access tunnels: Tunnel boring is commonly used to create access tunnels that provide entry points to different areas of the mine.
• Exploration drifts: Tunnel boring can be used to construct exploration drifts, which are horizontal tunnels used for geological mapping and sampling.
• Conveyor drifts: Tunnel boring is employed to create conveyor drifts that transport ore from the mining face to the processing plant.

E. Advantages and Disadvantages of Tunnel Boring

Tunnel boring offers several advantages, such as:

• High productivity: Tunnel boring machines can excavate tunnels at a faster rate compared to conventional drilling and blasting methods.
• Reduced disturbance: Tunnel boring minimizes the disturbance to the surrounding rock and reduces the risk of ground instability.
• Improved safety: Tunnel boring eliminates the need for blasting, reducing the risk of accidents and injuries.

However, there are also some disadvantages to consider:

• High initial investment: Tunnel boring machines are expensive to purchase and maintain.
• Limited to specific ground conditions: Tunnel boring is most effective in stable rock formations and may not be suitable for softer or fractured rock.

IV. Conclusion

A. Recap of the Importance and Fundamentals of Methods of Drivages

Methods of drivages are essential in underground metal mining for accessing ore bodies, providing ventilation, facilitating transportation, and ensuring the safety of miners. These methods involve various unit operations, including drilling, blasting, excavation, and support installation.

B. Summary of Raise Boring and Tunnel Boring

Raise boring is a method of drivage used to create vertical or inclined shafts, while tunnel boring is used to excavate horizontal tunnels. Both methods require specialized equipment and tools and have their advantages and disadvantages.

C. Overall Advantages and Disadvantages of Methods of Drivages in Underground Metal Mining

Methods of drivages offer several advantages, such as increased safety, precise drilling, and cost-effectiveness. However, they also have limitations, such as equipment requirements and restrictions on the type of drivages that can be created.

In conclusion, understanding the methods of drivages in underground metal mining is crucial for efficient and safe mining operations. By selecting the appropriate drivage method and considering the associated advantages and disadvantages, mining companies can optimize their production and ensure the well-being of their workers.

Summary

Methods of drivages play a crucial role in underground metal mining operations. These methods involve the excavation of tunnels, shafts, and raises to access and extract valuable mineral deposits. The selection of appropriate drivage methods is essential for ensuring the safety of miners, optimizing production efficiency, and minimizing costs. Methods of drivages refer to the techniques and processes used to create underground openings in metal mines. These openings provide access to ore bodies, facilitate the transportation of personnel and equipment, and enable the extraction of minerals. Various unit operations are involved in methods of drivages, including drilling, blasting, excavation, and support installation. Raise boring is a method of drivage that involves the excavation of vertical or inclined shafts, known as raises, from one level to another within an underground mine. This method is commonly used for ventilation, hoisting, and access purposes. Tunnel boring is a method of drivage that involves the excavation of horizontal tunnels, known as drifts, in underground metal mines. This method is commonly used for transportation, access, and exploration purposes. Both raise boring and tunnel boring have their advantages and disadvantages, and their selection depends on the specific requirements of the mining operation. Understanding the methods of drivages in underground metal mining is crucial for efficient and safe mining operations.

Analogy

Imagine you are building a house. Before you can start constructing the rooms and installing the utilities, you need to create the necessary openings, such as doors, windows, and hallways. Similarly, in underground metal mining, methods of drivages are like creating the openings that allow access to the valuable mineral deposits. These drivages serve as pathways for miners, machinery, and supplies, and enable the extraction of minerals. Just as different types of openings are required in a house, different methods of drivages, such as raise boring and tunnel boring, are used in mining to create the desired underground openings.