SAFETY
The 9911 HexArmor Chap completely eliminated belt conveyor maintenance and installation injuries
room in the thigh area to offer easy movement
and comfort, not to mention the chaps are cooler
and lighter than the leather alternative products.
Another benefit is that the chaps are fully
washable, lowering replacement costs and
improving hygiene.”
HexArmor also provides a wide range of PPE
such as protective gloves, arm guards, jackets,
and aprons. The mining industry demands grip
and dexterity to allow maintenan ce workers to
handle tools and knives without slipping under
extreme pressure. HexArmor has a variety of grip
solutions for the toughest mine site applications.
Mine lighting
In the lead to this article, the importance of
lighting has been demonstrated by Airfal. Nordic
Lights ® is one of the leading global suppliers of
Heavy Duty LED, HID & Halogen lighting
solutions. It defines Heavy Duty work lights as
“lamps specifically designed to be suitable for
use in extremely demanding environments and
applications. They are most commonly used to
provide illumination of working areas close to the
machine to which they are attached. However,
some heavy duty lights are also suitable for road
and signalling use.”
Nordic Lights provides useful reference
information, like the difference between lumen
and lux. “A lumen is the unit of measurement of
the complete quantity of light emitted by a light
source – the luminous flux. Lux is the quantity of
luminous flux on a surface. It decreases by the
square of the distance (inverse square law) of the
surface from the light source:
E(lx) = luminous flux (lm)/area (m 2 ).
“What is the difference between a lumen and a
candela? Lumen = luminous flux = the complete
quantity of light emitted by a source. Candela =
luminous intensity = quantity of light radiated in
a particular direction.
“Theoretical lumen output cannot be achieved
in real life. It is a calculated value showing what
would be possible under absolute ideal
conditions where no optical, electrical or thermal
losses occur in the system. This value can often
be 60% higher that the true lumen output.
“Operational lumen output takes thermal,
optical and electrical loss into account. It is the
true representation of the lumen output from the
lamp in real life conditions.
“Why do LEDs flicker, or appear to flicker?
Lamps using switched power supplies actually
turn the LEDs on and off extremely rapidly (<300
Hz). However, the human eye cannot see this (the
eye can only see flicker below about 200 Hz).
“If LED flickering is noticeable then there could
be various reasons:
n Cheap LED lamps may be designed with too
low LED switching frequency
n There may be a fault in the lamp circuitry
Recommended Nordic Lights’ LEDs for various
machines
n There may be an intermittent connection of a
component on the circuit board
n There may be an intermittent supply
connection to the lamp (eg loose, or poorly
plugged in connector)
n The flicker may be ‘fake’; eg the light may
actually be reflecting from a vibrating shiny
surface. So, the light itself isn’t flickering, but
because the shiny surface is moving rapidly, the
reflected light is also changing direction rapidly.”
Nordic Lights offers many different types of
LED work light. This is because an LED is not a
standardised light source like a halogen or HID
bulb. LEDs vary, particularly in physical size and
lumen output. This allows the flexibility to
produce lamp designs suitable for a wide variety
of applications and customer requirements. A
lamp with lower lumen output typically requires
less, or lower power LEDs than a lamp with a
much higher output. The lamp’s physical
dimensions, shape and lumen output can be
tailored for various situations. Using
combinations of lenses and LEDs can also create
products with identical appearance but with
differing light patterns and output.
On mounting lights, Nordic Lights notes that
aside from the physical dimensions and size of
mounting bolts, the main differences are in the
material used and their ability to withstand
vibration, shock and corrosion. Basic brackets are
made of steel and have basic shock & vibration
resistance. Cast brackets have a far greater
vibration and shock resilience. They are also
more corrosion resistant. “The best performing
brackets in terms of resistance to vibration and
shock are our patented Quake Damped brackets
available for the Scorpius range of lamps.”
HELLA Mining warns that there is currently no
universally recognised standard for measuring
the photometric properties of solid state (LED)
lighting. “This has
resulted in many
manufacturers and
resellers using
theoretical data (eg
raw lumens) which
offers no actual useful
comparison data for
the purchaser, who is
either unaware or
unable to calculate
the actual light output
taking into account
optical, electrical and
thermal losses. The
IES (illumination
Engineers Society)
released in 2008 a
standard for testing
amongst other things, the total luminous flux of
LED fixtures. This publication appears to be the
OCTOBER 2017 | International Mining