Adjustments and Errors in Mining Surveying

I. Introduction

In mining surveying, adjustments and errors play a crucial role in ensuring accurate and reliable surveying data. By understanding and addressing these adjustments and errors, surveyors can minimize uncertainties and improve the overall efficiency of mining operations.

A. Importance of adjustments and errors in mining surveying

Adjustments and errors directly impact the accuracy and reliability of surveying measurements. Inaccurate data can lead to costly mistakes in mining operations, such as incorrect tunnel alignments or inaccurate volume calculations. Therefore, it is essential for surveyors to understand and address adjustments and errors to ensure the success of mining projects.

B. Fundamentals of adjustments and errors in mining surveying

Adjustments refer to the process of aligning and calibrating surveying instruments to ensure accurate measurements. Errors, on the other hand, are deviations or mistakes that can occur during the surveying process. By understanding the fundamentals of adjustments and errors, surveyors can identify and correct any inaccuracies in their measurements.

II. Key Concepts and Principles

A. Temporary adjustments of Theodolites

Temporary adjustments are made to the theodolite before each surveying session to ensure its proper functioning. These adjustments include leveling, collimation, and line of sight.

1. Definition and purpose of temporary adjustments

Temporary adjustments are made to compensate for any misalignment or errors that may occur during the surveying process. These adjustments ensure that the theodolite is properly aligned and calibrated for accurate measurements.

2. Types of temporary adjustments

There are three types of temporary adjustments:

a. Leveling: This adjustment ensures that the theodolite is level and stable. It involves adjusting the leveling screws to align the bubble in the circular level.

b. Collimation: Collimation adjustment ensures that the line of sight is parallel to the horizontal axis of the theodolite. It involves adjusting the collimation screws to align the crosshairs with a distant target.

c. Line of sight: This adjustment ensures that the line of sight is perpendicular to the vertical axis of the theodolite. It involves adjusting the vertical tangent screw to align the crosshairs with a distant target.

3. Step-by-step process of performing temporary adjustments

The process of performing temporary adjustments involves the following steps:

1. Set up the theodolite on a stable tripod.
2. Use the leveling screws to level the theodolite.
3. Adjust the collimation screws to align the crosshairs with a distant target.
4. Use the vertical tangent screw to align the crosshairs with a distant target.

B. Permanent adjustments of Theodolites

Permanent adjustments are made to the theodolite to correct any misalignments or errors that cannot be corrected through temporary adjustments. These adjustments include horizontal axis adjustment, vertical axis adjustment, and collimation adjustment.

1. Definition and purpose of permanent adjustments

Permanent adjustments are made to ensure the long-term accuracy and reliability of the theodolite. These adjustments correct any inherent misalignments or errors in the instrument.

2. Types of permanent adjustments

There are three types of permanent adjustments:

a. Horizontal axis adjustment: This adjustment ensures that the horizontal axis is perpendicular to the vertical axis. It involves adjusting the horizontal tangent screw.

b. Vertical axis adjustment: This adjustment ensures that the vertical axis is perpendicular to the horizontal axis. It involves adjusting the vertical tangent screw.

c. Collimation adjustment: Collimation adjustment ensures that the line of sight is parallel to the horizontal axis. It involves adjusting the collimation screws.

3. Step-by-step process of performing permanent adjustments

The process of performing permanent adjustments involves the following steps:

1. Set up the theodolite on a stable tripod.
2. Use the leveling screws to level the theodolite.
3. Perform the temporary adjustments as mentioned earlier.
4. Use the appropriate adjustment screws to correct any misalignments or errors.

C. Sources of errors in mining surveying

Errors can occur due to various factors in mining surveying. These errors can be categorized into instrumental errors, environmental errors, and human errors.

1. Instrumental errors

Instrumental errors are caused by imperfections or misalignments in the surveying instrument.

a. Imperfections in the instrument: These errors can occur due to manufacturing defects or wear and tear of the instrument. Examples include incorrect graduations on the instrument's scales or loose components.

b. Misalignment of the instrument: Misalignment errors occur when the instrument is not properly aligned or calibrated. This can result in inaccurate measurements.

2. Environmental errors

Environmental errors are caused by external factors that affect the surveying measurements.

a. Atmospheric conditions: Changes in atmospheric conditions, such as temperature, pressure, and humidity, can affect the accuracy of surveying measurements. For example, temperature variations can cause the expansion or contraction of the instrument, leading to measurement errors.

b. Magnetic disturbances: Magnetic fields in the vicinity of the surveying area can interfere with the instrument's magnetic compass or electronic components, resulting in errors in measurements.

3. Human errors

Human errors are caused by mistakes or inaccuracies made by the surveyor during the surveying process.

a. Misreading of measurements: Misreading errors occur when the surveyor misinterprets or misreads the measurements on the instrument's scales or vernier scales.

b. Incorrect setup of the instrument: Errors can occur if the surveyor does not set up the instrument properly or does not follow the correct surveying procedures.

D. Prevention of errors in mining surveying

To prevent errors in mining surveying, the following measures can be taken:

1. Regular calibration and maintenance of instruments: Surveying instruments should be regularly calibrated and maintained to ensure their accuracy and reliability. This includes checking and adjusting the instrument's components, such as leveling screws and adjustment screws.

2. Proper training and supervision of surveyors: Surveyors should receive proper training on the correct operation and maintenance of surveying instruments. They should also be supervised to ensure that they follow the correct surveying procedures.

3. Use of appropriate surveying techniques and procedures: Surveyors should use the appropriate surveying techniques and procedures for different mining surveying tasks. This includes using the correct adjustment procedures and applying appropriate corrections for environmental factors.

III. Typical Problems and Solutions

A. Problem: Misalignment of the instrument

1. Solution: Perform collimation adjustment

If the instrument is misaligned, a collimation adjustment can be performed to correct the misalignment. This involves adjusting the collimation screws to align the crosshairs with a distant target.

B. Problem: Atmospheric conditions affecting measurements

1. Solution: Apply appropriate corrections based on atmospheric conditions

If atmospheric conditions, such as temperature or pressure, are affecting the measurements, appropriate corrections can be applied. For example, temperature corrections can be applied based on the temperature variations to compensate for the expansion or contraction of the instrument.

C. Problem: Misreading of measurements

1. Solution: Double-check measurements and use proper reading techniques

To avoid misreading errors, surveyors should double-check their measurements and use proper reading techniques. This includes ensuring that the instrument is properly aligned and reading the measurements accurately from the instrument's scales or vernier scales.

IV. Real-World Applications and Examples

A. Adjustment and error prevention in underground mining surveys

In underground mining surveys, adjustments and error prevention are crucial for accurate tunnel alignments and volume calculations. By performing regular adjustments and applying appropriate corrections, surveyors can ensure the safety and efficiency of underground mining operations.

B. Adjustment and error prevention in open-pit mining surveys

In open-pit mining surveys, adjustments and error prevention are essential for accurate volume calculations and slope stability analysis. By addressing adjustments and errors, surveyors can minimize uncertainties and optimize the design and planning of open-pit mining operations.

V. Advantages and Disadvantages

A. Advantages of adjustments and error prevention in mining surveying

1. Improved accuracy and reliability of surveying data: By addressing adjustments and errors, surveyors can improve the accuracy and reliability of surveying measurements. This leads to more precise calculations and better decision-making in mining operations.

2. Minimization of errors and uncertainties in mining operations: Adjustments and error prevention help minimize errors and uncertainties in mining operations. This reduces the risk of costly mistakes and improves the overall efficiency of mining projects.

B. Disadvantages of adjustments and error prevention in mining surveying

1. Time-consuming process of performing adjustments: Performing adjustments can be time-consuming, especially when multiple adjustments are required. This can slow down the surveying process and potentially delay mining operations.

2. Cost of regular calibration and maintenance of instruments: Regular calibration and maintenance of surveying instruments can be costly. This includes the cost of equipment, calibration services, and maintenance labor. However, the benefits of accurate surveying data outweigh the costs in the long run.

Summary

Adjustments and errors play a crucial role in mining surveying to ensure accurate and reliable surveying data. Temporary adjustments, such as leveling, collimation, and line of sight, are made before each surveying session to align and calibrate the theodolite. Permanent adjustments, including horizontal and vertical axis adjustments, and collimation adjustment, are made to correct misalignments or errors that cannot be corrected through temporary adjustments. Errors in mining surveying can be caused by instrumental, environmental, and human factors. To prevent errors, regular calibration and maintenance of instruments, proper training and supervision of surveyors, and the use of appropriate surveying techniques and procedures are essential. Typical problems, such as misalignment of the instrument or atmospheric conditions affecting measurements, can be solved through collimation adjustment or applying appropriate corrections. Adjustments and error prevention have real-world applications in underground and open-pit mining surveys, improving accuracy, reliability, and minimizing errors and uncertainties in mining operations. While adjustments and error prevention can be time-consuming and costly, the benefits of accurate surveying data outweigh the costs.

Analogy

Adjustments and errors in mining surveying are like calibrating a compass before going on a hike. Just as calibrating the compass ensures accurate navigation, adjustments and error prevention in mining surveying ensure accurate measurements and reliable surveying data. Without proper adjustments and error prevention, surveyors may encounter inaccuracies and uncertainties, similar to getting lost on a hike due to an inaccurate compass.