COAL
Touchstone has earned numerous awards as an industrial problem-solver,
new product developer, and applied research laboratory for hundreds
of manufacturers in a wide range of business sectors. Our unique
capability as an industrial problem-solver is based on the diversity
of our highly experienced technical staff, supported by over $10
million worth of in-house laboratory equipment and testing facilities.
The following examples illustrate some of our contributions to this
business sector:
- Five roof plates and four washers that failed in service, and
three plates that were not used, were examined. Touchstone concluded
that cracking at the bolt hole resulted from circumferential tensile
stresses that built up from distortion of the plates as a result
of the force from the bolt and washer assembly at the circumference
of the washers.
- An investigation of a cracking failure in a linepan floor plate.
Cracking in longwall pan floor plate was examined and found to
be the result of substandard plate used in fabrication. The cracks
developed longitudinally in several of the individual longwall
machine segments. Elemental analysis and charpy tests demonstrated
that the plate did not meet mechanical property requirements and
developed cracks under the impact of falling coal and rock.
- Touchstone was contacted concerning a failure in use of the
drive shaft of an electric induction motor. Touchstone was asked
to determine the cause of the failure and suggest a solution to
the problem. Analysis showed that little or no radius was provided
at the location of a change in shaft diameter where a ball bearing
fit onto the shaft. The resulting stress concentration caused
the shaft to fail catastrophically after only a short service
life.
- Degrading performance of celtite epoxy used to secure mine roof
bolts was brought to the attention of Touchstone engineers. Eight
celtite cartridges, 4 labelled new formula and 4 labelled old
formula, were delivered to Touchstone for evaluation. A GCMS analysis
was performed on the samples. No difference was detected between
the new and old formula celtite resin cartridges, indicating that
some other cause for the poor performance was in effect.
- Touchstone engineers examined a Contactor Enclosure and an Operator
Control Station Enclosure which had been recovered from the site
of an underground coal mine explosion. It was requested that Touchstone
determine if an explosion or fire had occurred within either of
these enclosures. Based on Touchstone's experience with such failures
and testing of evidence, it was concluded that no recent fires
or explosions had occurred within either of these two enclosures.
- Touchstone evaluated a mine equipment methane sensor which was
suspected of failure. The question of lead wire breakage on the
internal sensor bead was resolved by SEM examination of the broken
wire end. The presence of fatigue striations on the broken end
showed that vibration had probably caused the unit to fail. The
equipment design, however, still allowed the equipment to operate
regardless of local atmospheric conditions. The system was redesigned
to provide "fail-safe" operation where the previous
design could allow sensor failure yet allow equipment to operate.
- Touchstone is involved in the development of coal-based pitch
products. The laboratory has been equipped to produce carbon-based
foam material that has strategic mechanical properties including:
thermal stability, low density, structural integrity, and the
ability to be bonded using polymer based and pitch based adhesives.
The above examples are only a sample of our work in this area.
We would be pleased to provide any additional information you may
require. We also invite you to review examples on our website of
work that we have performed in support of other business sectors.
Please contact one of our Project
Managers to discuss your manufacturing problem. We would welcome
an opportunity to add you to our rapidly growing list of satisfied
customers.
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