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CASE STUDY-REXROTH

Rexroth’s AA11VLO series of axial utilize one of the existing pilot holes
piston variable displacements pumps to drill a rescue portal, and would
are designed for hydrostatic drives not have to be emplaced directly
in open circuits. They offer high above the miners.
power capacity and displacement • The T130XD in Chile was equipped
in a compact design, with nominal with Schramm’s highest capacity top
pressure of 5100 psi (350 bar) and head, capable of drilling holes up to
maximum pressure of 5800 psi (400 28 inches in diameter.
bar.) The AA11VLO130 is equipped • The T130XD is designed for fast
with a charge pump enabling high teardowns and relocations, enabling
input speeds, which is especially it to make the 1,000 km trip in
important at high-altitude operation, relatively short time.
like Chile. Its 130 cc/rev (7.93 in /rev)
3
The reliability of the Rexroth AA11VLO can operate at engine speeds up to Given the advantages offered by
pumps is especially critical in deep drilling
applications requiring high pressure 2,500 rpm. the T130XD, the Chilean mining
capacity and pullback force delivered by authorities developed a “Plan B”
the drill rig.
When the Chilean government sent rescue plan: the T130XD would
out the call across the country for enlarge one of the 5.5-inch diameter
T130XD was designed for drilling
assistance, it was determined that the initial probe holes, drilled with two
applications such as shallow oil and
T130XD rig offered several potential passes. The first pass would increase
gas, deep water wells, geothermal
exploration and...deep mine rescue. advantages for the rescue: its diameter to 12 inches and the
• The T130XD is well-suited for second pass to 28 inches diameter, to
A key component of the hydraulic drilling with reverse-circulation allow a rescue rig to be lowered.
system that powers the Schramm down-the-hole hammers, making it
drill are the Rexroth AA11VLO especially ideal for drilling through Putting Plan B into action
variable displacement axial piston the Chilean granite. Arriving at the San Jose mine on
pumps, supplied by local Rexroth • Schramm’s rig was designed to drill September 30, the T130XD was
distributor Airline Hydraulics, Inc. off a vertical axis, enabling it to quickly set up and drilling on the
(Bensalem, PA ).
Schramm selected the Rexroth
AA11VLO130 pumps when designing
the T130XD because of their proven
performance, particularly in deep
drilling applications requiring the high
pressure capacity and pullback force
delivered by the rig.
Schramm’s drill uses four Rexroth
AA11VLO130 pumps, which supply
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hydraulic pressure to the top mast
head and mast cylinders. The top
mast head is the mechanism at the
top of the drill mast that provides Photo courtesy of Schramm, Inc.
the pullback force to manipulate
thousands of feet of pipe down the
hole; the mast cylinders support
The variable displacement pumps on the T130XD supply hydraulic pressure to the top
this function. mast head for manipulating thousands of feet of pipe.

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| Global MDA Journal | NOV-DEC 2017