Our solution for mine shaft inspection routine is designed for underground mines in order to provide safe and more effective mining operations. The software component of this solution is called Shaft Inspector and it is usually used for post-processing of 3-dimensional laser scanning data collected by Mine Shaft Scanning System (MS3) which is a tool for the regular inspections, monitoring and profiling of mineshafts.
Shaft Inspector consists of a few principle software components:
- database of mine shaft constructive elements and scans ( based on SQL Server or Oracle);
- data accessing and data processing algorithms;
- a data presentation and data visualisation layer.
Purpose separation of components gives an opportunity to review, to amend, to change or even to substitute parts of each module without affecting other modules in order to tune up the solution to meet client’s requirements. Logical connection between the modules facilitates an effective work flow for data processing in order to make it fast, convenient and well controlled.
The work flow suggested by Shaft Inspector imposes the following stages of implementation:
1. The creation of a mineshaft constructive elements database
The constructive element database is the informational heart of the technology. It can be effectively used either as a separate product or in combination with MS3. The constructive element database may assist technical personnel in providing a fast and convenient way to keep track of all the changes, construction work, modifications and repairs done inside the mine shaft and/or its headgear.
Mine shaft constructive element database can be created in two ways:
- From the existing drawings of the mine shaft (elevations, layouts, cross-sections, etc.) in any contemporary engineering CAD formats.
- From the initial 3-dimensional laser scan with the following specialised processing of the obtained “point cloud”.
Both methods can be combined in certain cases for higher quality of the results. Special semi-automated tools assist in the creation of mine shaft constructive elements database.
2. Modelling of device configuration
Each mine shaft is unique, so the main challenge for the designers of MS3 is to configure the generic MS3 system for the particular mine shaft conditions.
In order to make this process well defined and consistent, a special mine shaft scanning simulation tool has been developed. Using the initial mine shaft model and setting up certain parameters (number of scanners, their speed and angle of scanning, orientation etc.) the tool assists the designer in finding the optimal solution and the most appropriate MS3 configuration.
- using the developed tool one can define the best configuration of MS3 for the particular mine shaft;
- the tool allows to define number of required scanners, their orientation, position and parameters prior to the assembly of the real system;
- the purpose is to provide the best possible quality of scans (no blind spots or minimum known blind spots, sufficient density of points vs. scanning speed, etc.).
3. Processing the initial scan and updating the initial model
After assembly of the device it is necessary to make the initial real scan. The initial mine shaft model made from the original technical drawings could be sometimes generalised or not sufficiently accurate. The first real scan provides an opportunity to improve the accuracy of the mine shaft constructive elements database, sometimes to update it with the newly installed elements and to make an amendment to the description of topology, metrical and other properties. It is also required at this step to define all deviation tolerances for sets of parameters that are subject to an inspection check.
- the mineshaft element database is reviewed taking into account the differences revealed between the preliminary “theoretical” description of elements and the initial “real” scanning results. The description of elements should be put in a compliance with the actual status;
- the obtained database is set up as an etalon (template) for any further automated inspections;
- a database of defects with permissible deviation tolerances and thresholds is generated.
4. Acquiring and analysing the regular inspection scans
The mining laws which are stipulated in practically all countries with a mineral-extracting industry state that a mine shaft inspections must take place on a regular basis and according to certain schedules: once a day, once a week, once a month etc. In the MS3 technological paradigm this means that new scans will be captured and uploaded to the database regularly, following the predetermined schedule of inspections. Scanning can be also complemented by digital high resolution coloured photos or videos taken simultaneously.
As soon as the new scan becomes available Shaft Inspector begins the processing. The following logic is implemented:
- the comparison of the last scan with both the etalon (template) shaft model and a previous scan is made in order to locate problematic areas including cracks in lining, misalignment of pipelines, buntons and guides, etc. and to visually highlight all elements and zones that have undergone some changes;
- the report which contains the records for all the revealed differences during the mentioned comparison is generated;
- using built-in algorithms, the engineer responsible for mine shaft operations generates a repair and maintenance order or a job card (to fix the revealed problems) based on the report analysis and a visual analysis of the last scan and provided pictures;
- after completion of the repair works the etalon mine shaft model must be updated since the new status of fixed elements must be accepted as new guideline.