Mine Shaft Scanners Automates Inspection

A Parsec case study about the development of a mineshaft scanning system that
will automate inspection without the need to shut down production

Parsec 1

Accurate models created from millions of data points obtained from mineshaft
scanners save time and prevent errors when planning, installing and maintaining
infrastructure. Traditional surveying gathers limited data in most environments, which
may impact on accuracies in material estimations and engineering plans.

Mines are legally obliged to do regular visual inspections of their shafts. A manual
process interrupts normal operation for several hours, which results in a loss of
production and revenue. It is a tedious process which can lead to an oversight of
defects.

Sight Power (www.sight-power.com), a company specializing in the development of
analytical information and data modelling systems for mining, oil and gas industries,
approached Parsec to develop an automated solution to prevent undue interruption
of the production process yet meet the legal requirements. Parsec took on the
challenge to design and develop a concept demonstrator of the Mineshaft Scanning
System (MSSS).

The MSSS main components consist of a controller connected to various geo-
reference and optical sensors, the mechanics hosting these entities and an operator
console for control and maintenance of the system. Parsec subcontracted the
mechanical design and construction of the system to MMS Technology
(www.mmstechnology.co.za).

Parsec’s objective with the MSSS project was to provide a development service to
their client which provided them with a platform to prove a concept. Once the
concept has been proven, follow up development work may potentially evolve, which
can be embedded into the client‘s product. The expectation is that the development
of the demonstrator will in the long term allow Parsec to expand its activities in the
industrialization and outsourced manufacturing of the product.

Comprehensive approach to achieve the end goal
The main requirement of the MSSS is to provide a detailed 3D-scan of the mineshaft
environment (this includes the shaft lining, steelworks, cables, ropes and other
construction elements) with a predefined density of reflected points. Data gathered
from each laser sample of the laser scanner, is time and geo-tagged to enable off
line reconstruction and processing of the shaft image.

The project consists of three phases, namely a definition, implementation and
integrate & test phase. The definition phase duration was 10 months, and was
initiated in July 2011 with an extensive feasibility study during which academics
specialising in the field of inertia were consulted. Various laser scanners, Inertial
Navigation Systems (INS), accelerometers, inclinometers, distance sensors (eddy,
laser, encoders) and cameras available in the market were evaluated during this
process. This included visits to manufacturers to obtain first-hand knowledge of the
products.

This was followed by the creation of a user requirement specification as well as a
system specification. Enterprise Architect, a high performance modelling,
visualizationand design platform, was used to dissect the requirements into Unified
Modelling Language (UML) Use Cases. These Use Cases were further elaborated
on in software, hardware and mechanical design documents used by the
development engineers. It was decided to do validation of the sensors and collected
data as early as possible during the development process. Test applications and
mathematical models were created to assist with this de-risking initiative.
The implementation phase started directly thereafter, and produced a laboratory
prototype model which at present is being exercised in the laboratory. This phase
lasted for 9 months, and the project is currently making the transition from
implementation to the integration & test phase.

As with Parsec’s total project portfolio, this project was also executed under the
Project Management Body of Knowledge (PMBoK) framework.

Parsec 2Block diagram showing the controller connected to various geo-reference and optical sensors.

High-bandwidth FPGA PMC module to overcome shortcoming of the OS
The design team was faced with some interesting challenges. Being a concept
demonstrator and taking into account time to market, the decision was taken to use
off the shelf components wherever possible. An industrial PC, running Microsoft
Windows OS, was used as controller, which did not guarantee the timing
requirements aimed for. To overcome this obstacle, one of Parsec’s Commercial
products (the PM432 high-speed, high-bandwidth FPGA PMC Module, (
www.parsec-group.com/blog/parsec/downloads/Parsec_PM432.pdf) was used in the controller. This module very accurately provides PCI interrupts to the software for timing sensor sampling and external clocking for sensor synchronisation.

The logistics of setting up a test environment for the product was another challenge
the design team was faced with. The lab constraints forced the team to assemble the
scanner horizontally as opposed to the vertical position it is intended to operate in.
Rails had to be constructed for the scanner to move on and a cranking mechanism
was introduced to simulate the rough movement experienced in the mining
environment. This setup proved to be adequate for demonstrating the concept under
investigation.

One of the requirements of the project was for Parsec to provide its customer with
reliable data recorded from the various optical and geo-reference sensors. This
entails producing repeatable scans where the accuracy between scans is within the
design specification. Mathematical models were built in Matlab to do post processing
of the recorded data. This enabled the development team to identify synchronization
and latency issues at an early stage and take corrective measures.
It was always going to be a challenge to synchronize data originating from different
sensors. The design team had to go through a number of iterations before
accomplishing the goals set out in the requirements. The mathematical models used
during data analysis were crucial in fine tuning the system. Extensive testing was
also done on a sub-system level throughout the project. A test application was
written for each sensor type to validate the driver and get a feeling for its accuracy
and responsiveness.

Parsec prides itself on its ISO9001 accredited processes which guided this project
through the different phases of its life cycle. Regular communication with the
customer also proved helpful to manage expectation on progress and delivery.
Conclusion Through developing the concept demonstrator for an automatic mineshaft scanner, Parsec has proven its ability to supply a customized all-inclusive solution to their
customer. The company is well positioned to be involved in the subsequent phases
of the project, which will cover mine testing and the development of a production
unit.

Valuable lessons learned include the importance of de-risking throughout the project
life cycle. It is important to validate each sub-system as soon as possible and identify
potential problems.

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