Spatial positioning of sidewall stations in a narrow tunnel environment: a safe alternative to traditional mine survey practice

Interpretation based on the SWOT analysis.

The various SWOT analysis performed on the available technologies evaluated the individual attributes of each form of technology. In order to select the best combination of technologies, the following questions were asked.

1.13.How can the strengths of the method or technology be used to overcome the identified threats?

Table A SWOT interpretation: How can strengths used to overcome threats?

Strength	Threats
Gradestring installation is self-checking by visual inspection. Should the strings not align perfectly, damage should be suspected.	Grade pegs can be damaged easily and can be the cause of off-line or off-grade development
Laser provides a visible alignment of marks and gradient	Grade pegs can be damaged easily and can be the cause of off-line or off-grade development
Laser technology is affordable	Laser can go out of alignment or be damaged or lost
Laser is proven technology and adaptable	Technology not widely used in mining Surveyor requires training to accurately install laser Laser control in mining has been limited due to perceived cost constraints Some lasers not suitable for long distances, straight or curved ends

1.14. How can the strengths of the method/technology be used to take advantage of the opportunities?

The advantages of using laser technology is widely recognized but not applied to the same extent in the mining industry. Conventional setting-out methods specifically designed for use with hangingwall survey control is still considered best practice. It is necessary to address this state of affairs to take advantage of the possibilities offered by laser and other technologies.
Table A SWOT interpretation: How can strengths used to take advantage of opportunities.

Strength	Opportunities
Gradestring method is cost effective.	Low cost can make implementation approval easier.
Gradestring installation is self-checking by visual inspection.	Known technology can be adapted to serve a modified purpose in the control of direction. Intersection points can be checked and replaced by means of calculated tie distances.
Visible alignment of marks and gradient.	Laser technology provides a bright line or spot visible over a long distance, far more accurate than conventional alignment using cap lamps and strings.
Laser technology is affordable.	Laser technology is extensively used in tunnel construction and is proven and reliable. Laser control in mining has been limited due to perceived cost constraints.
Accurate longer sighting distances are possible.	Surveyor can focus on establishing accurate survey networks and perform less setting-out tasks. Laser can be used to mark paint lines for excavation control.

1.15.How can the weaknesses be addressed to take advantage of the opportunities?

The weaknesses of laser technology and the setting-out methods have been identified. The opportunity lies in the development of technologies to address these points. A number of adaptations of laser technology such as the sleeve laser, duel-beam laser and string mounted laser have been developed to suit the needs of users within industry.

Table A SWOT interpretation: How the weaknesses be addressed to take advantage of opportunities

Weakness	Opportunities
Setting-out instructions can be interpreted incorrectly.	Gradestring installation is self-checking by visual inspection. Proven technology makes adaption of process easier when looking at best-practices in setting-out and marking-up.
Gradestring offsets can be misidentified.	Known technology can be adapted to serve a modified purpose in the control of direction. Intersection points can be checked and replaced by means of calculated tie distances. Laser technology provides a bright reference point over a long distance.
Misalignment of laser with control marks and gradient.	Laser technology is becoming affordable, devices can be replaced. Calibration of all laser devices possible.
Longer sighting distances are possible can cause a large error in development.	Self-checks for laser in place, such as audible alarms, sighting targets obscuring the laser beam when misaligned. Laser alignment done by surveyor. Laser line can be routinely inspected and maintained by the surveyor. Mounting can be done in a safe area away from disturbance. Portable laser can be removed. The direction and grade lines can be indicated and painted in during the laser installation by the surveyor.
Lasers are not suitable for all tasks.	Technology is flexible and adaptable to purpose, including long- or short range applications and mounting methods.

1.16.How can the weaknesses be minimized to take overcome the threats identified?

The weaknesses of laser technology and the setting-out methods have been identified. The main method of addressing the threats identified is to ensure a procedure of installing, maintaining and servicing lasers in-situ is introduced and followed. The introduction of self-checks such as misalignment target plates or alarms coupled with logic checks performed to see if the laser beam conforms to the existing gradient and line of the excavation should be encouraged.

Table A SWOT interpretation: How the weaknesses are addressed to overcome the identified threats.

Weakness addressed	Threat
Setting-out instructions can be interpreted incorrectly. Mitigate the threat by: The use of proven technology makes adaption of process easier when looking at best-practices in setting-out and marking-up. Change management must be part of the implementation phase. Training of surveyors and production crew on clear communication is required. Introducing visual checks in the process.	Off-line and off-grade development can lead to cost implications and reserve sterilization.
Maintenance of laser and direction control required. Mitigate the threat by: Regular maintenance of laser line on site. Regular service of laser devices. Mounting position of laser device. Remove device when mark-up has been done.	Off-line and off-grade development implications. Accuracy of “mark-up” dependant on technology and accuracy of setting-out process. Misalignment of laser with control marks and gradient.

6.