Product focus
Allis-Chalmers built two sets of 92cm diameter by 152cm face sledging
crushers in 1911 for the Casparis Stone Company’s flux limestone plant
in Fairmount, Illinois, giving rise to the name Fairmount crushers. This
Fairmount crusher is located at Ruffner Mountain in Alabama.
The manual screening of ore through a sieve.
This image is dated March 1930.
cam that used gravity to boost crushing power
— was documented in ancient China as far
back as 40 BCE and was possibly in use at least
1 000 years before that. The implementation of
the cam and cogwheel — which date back to
Greek polymath Archimedes’s involvement in
the development of gears in the third century
BCE — in the crushing process allowed
for continuous operation, greatly increasing
processing efficiency.
Despite this documented early use of tools
to assist in the crushing process, we still see the
manual processes of hammer crushing and hand
sorting used across Africa today to produce
materials such as gravel.
This was also the first reference to screening
directly with the crushing process. Typically, the
crushing machines were essentially designed to
crush material to a certain size, but the screening
of the material was still a manual process,
as the crushing process could not create an
equivalent and consistent crushed product, so
hand screening was still applied. When demand
grew beyond the capabilities of one crusher, it
was generally a simple matter to add a second
machine, and so on.
The next era
It was only after explosives and early powerful
steam shovels (initially invented by Grimshaw of
Boulton & Watt in 1796) with the ability to load
large chunks of material for transporting bulk
aggregates by rail were invented that crushing
became widespread. The steam shovel began to
change the entire picture of open-pit operations.
At the same time as industry was looking to
build ever-larger primary crushers, the single,
The earliest US patent for a crushing machine
was issued in 1830. It covered a device
essentially incorporating the drop hammer
principle later used in the famous stamp mills,
whose history is intimately linked with that of
the golden age of mining. Eli Whitney Blake
invented the first successful mechanical rock
breaker: the Blake Jaw crusher, patented in 1858.
Blake adopted a mechanical principle familiar
to all students of mechanics today, namely the
powerful toggle linkage. The Blake-type jaw
crusher concept is the standard by which all jaw
crushers are judged today.
In 1881, Philters W. Gates was granted
a patent on a machine that included in its
design all the essential features of the modern
gyratory crusher. For many years after these
pioneer machines were developed, requirements
remained very simple. All mining and quarrying,
whether underground or opencast, was done
by hand; tonnages were generally small and
product specifications simple. Even the largest
commercial crushed stone plants were small,
consisting of one crusher — either jaw or
gyratory — one elevator, and one screen.
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AUGUST 2017
Advancing mechanics
sledging roll crusher was born. The Allis-
Chalmers Company built two sets of 92cm
diameter by 152cm face sledging crushers in
1911 for the Casparis Stone Company’s flux
limestone plant in Fairmount, Illinois, giving rise
to the name Fairmount crushers. The machine
quickly achieved a high degree of popularity, and
although its field of application was relatively
limited, quite a number of these machines were
installed for primary crushing.
In 1919, the largest gyratory crusher yet built
was manufactured by Traylor Engineering — a
152cm machine eclipsed in size only half a
century later when the company built the first
183cm gyratory crusher. This remained the
world’s only operating gyratory crusher of that
size until it was replaced in 2001.
By 1920, the hammer mill had been
developed to produce a finer product in a
single-pass machine. These machines employ
the impact principle of breaking stone. The
hammer mill has a simple mechanism. The
Manual labour to crush rock is still widely used across Africa. Here two young Ugandan boys work
their pile of rock to gravel.