HDD rock drilling in the Alpine Mountains - Prime Drilling GmbH

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TRECNHLESS TECHNOLOG Y
HDD rock drilling in th e
Alpine Mountain s
Impressive job sites from Italy, Switzerland, Germany, Slovenia ,
Austri a
By Dr. Hans-Joachim Bayer
Horizontal directional drillings in high mountains or even in the boulder and gravel determinated
foreland are much more complicate and need more experience and more specia l
knowledge than areas with lower relief differences .
Natural gas pipelines, waterpipes e .g. for artificial snowing in winter sport regions, sewers ,
cables and other connections use in the high mountains often the shortest possible way,
and this means in many cases through the rock formations, straight through the ridges ,
saddles, crests, buttes, peaks and rock noses, below wild rivers, below natural reserves ,
into caves or artificial caverns and tunnels .
Very different job sites with very different tasks are shown in this article and especially thei r
solutions under wide spread different rock conditions and rock changements in the bor e
trace were figured out. Examples from the Basel region, the area of Films and Laax (Eas t
Switzerland), the Bavarian Alps and Alpine Lakes, the Slovenian Karst region, Austria n
rivers and Italian Alps and foreland were demonstrated and their excellent rock drillin g
solutions are presented .
Rhine river crossing in Alpin e
Boulders in Basel (CH )
Basel is an economically strong Swiss cit y
with a French airport, a German central sta-
tion and the north side of the Alpine foreland
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range of the Swiss Jura . Large chemical an d
pharmaceutical companies have their hea d
offices and their main production plants i n
Basel . Some of these companies have thei r
production sites direct on both sides of th e
Rhine river and sometimes, more and more
e
pipe connections under the river got necessary,
as described in the following crossin g
project .
The Rhine river flows through a relatively narrow
and deep bed in the municipal area of
Basel, with buildings and traffic ways on bot h
sides in the immidiate vicinity . In every sens e
of the word, Basel is "closely" connected wit h
the Rhine, which changes directions of th e
"Alps Rhine" to flow as the "Upper Rhine" t o
the north . This gate position leads a pile up of
gravel, blocks and boulder material of 17 m
below the river floor. Many boulders have a
half meter and even more in diameter an d
they consist of naturally transported material
from the central and the northern Alps .
Underneath lie solid clay and sandy mar l
horizons in a close succession with grave l
and boulder horizons, which have completel y
opposite properties, when drilling technique s
are concerned .
A large chemical manufacturer commissioned
a Swiss building contractor to instal l
a network of empty PE-pipes beneath and
also below the Rhine river to take fiber opti c
cables for intra-company communication facilities.
A segment of the required installatio n
was the undercrossing of the river in a dept h
of 24 m .
In awareness of these difficult underground
conditions, the contractor chose a 50 t drillin g
unit from Prime-Drilling, particularly becaus e
the lenght of the undercrossing was to b e
400 m . The 50 t rig was an excellent choic e
for this job, because of their good drillin g
abilities, even when taking the difficult underground
and the confined space into account .
Beside the PD 50/33, a recycling system fo r
1000 liters of drilling fluid per minute wa s
placed . The machine was equipped with a
mudmotor bearing a 200 mm drill head wit h
TCI-bits for the gravel and stone area an d
with mill toll bits for the clay stone and sand y
marl below a depth of 17 m for the pilot bore .
The roller bit head had to be driven out an d
exchanced four times during the pilot bor e
because of the constantly alternating geo -

logical conditions . Several days of work wer e
required for the pilot bore . The first expansio n
was carried out with a 350 mm hole opene r
with TCI-bits, while a hole opener with a diameter
of 450 mm was used for the secon d
reaming operation . A third check reaming followed
with the 450 mm hole opener and a
fly cutter attached at the back . The 355 m m
host pipe was pulled into the 450 mm bor e
hole as a final working step . The whole projec t
in this difficult underground, in close conditions
between the factory buildings and wit h
a river crossing depth of 24 m and the complete
cable installation was finished within si x
weeks .
Parallel drillings in the Kars t
limestones of Sloveni a
The caverns of Postojna in the Karst regio n
in the foreland of the "Julian Alps" (Area i n
the Southeastern part of the Alps) are ver y
famous and are known as one of the most
impressive natural wonder in Europe and a
main tourist attraction in Slovenia . The Cav e
labyrinth, stretching over 27 km, with its extraordinary
amount of stalactites, stalacmite s
and sintering covers, is also the ideal livin g
area of the very seldom cave lurch, an unpigmented
species of amphibian .
The tour starts some decameters behind th e
cave entrance with a special cave train . A
railway line follows a round tour through th e
rows of underground cave halls . The battery
operated cave platform train are regularly reloaded
at a central loading station . After years
of operation the renovation of the loading station
was to be carried out . For practical reasons
the cave administration team decided t o
re-locate the loading station from the inside t o
the outside of the cave . In order to do this a
connection line had to be produced .
The open-trench method was ineligible due t o
the installation length and the extremely ston y
ground . The responsible planners therefor e
decided an a direct connection . This required
two rock drillings through the cave wall, eac h
at 30 m lenghts at a distance of 1 meter fro m
the outside to the inside .
A Grundodrill 13X HDD unit of the compan y
VILKOGRAD (Sentjur, Slovenia) was applie d
for this task (Figure 1), a leading company
for trenchless pipe renewals and horizonta l
bores in Slovenia, Croatia and neighborin g
countries .
To determine the optimal starting point, th e
direction and the inclination angle were measured
before with a laser-theodolite . A Grundorock-Mudmotor
was used to establish th e
pilot bore through the extremely hard lime-
stone, which took about 30-40 minutes fo r
the 3 m Jong drill rods . The advantage of th e
Grundorock-Mudmotor is the fact, that only a
relatively small quantity of drilling fluid is required
for the operation . The roll and pitch of
TRENCHLESS TECHNOLOG Y
Fig . 2 : HDD rock drilling in an altitude of nearly 2000 m, in the Glarn Alps, Eastern Switzerlan d
the mud motor was controlled precisely with
a cable guided measuring system .
The enlarging bores then followed with a 10 "
hole-opener (equals a diameter of 250 mm) .
Then steel pipes ND 219 were brought in th e
bore hole by means of an Olymp rammer . ,
Last, the power cables were installed for th e
connection to the new loading station . Afte r
only 6 days the construction work around th e
rock drilling was completed by the Vilkogra d
Crew .
Crossing the Traun River nea r
Chiemsee at the Bavarian Alps
The Traun river, a really "wild" river, comin g
directly from the Bavarian Alps, shows even i n
the foreland, few kilometers in front of northern
Alpine chains, a strong hydraulic incline in th e
flow and also in the connected groundwate r
flow besides and below the river ground . Th e
water levels of the river can change suddenly ,
according to rain occurrences in the mountains
. An open river crossing for pipe laying o f
two parallel pipes in two meters distance (P E
pipe water 110 mm in diameter and PE pip e
sewer 180 mm) was too dangerous, so th e
communal network owner decided for a HD D
river crossing and gave that task to the experienced
company Max Wild from Illerbachen ,
which is located in the Alpine foreland .
The geology at the river crossing site near
Traunreut is determined by the glacial freight
of a former terminal moraine, so this area beside
and below the Traun river is overfreighted
by glacial debris from fine grain materia l
up to blocks and boulders . The challenge for
every HDD drilling company is the permanent
extreme change between very hard and sof t
material, in shortest distances, in the termina l
moraine .
So the river crossings were operated with a
Grundodrill 20 S HDD unit and with a Grundorock-Mudmotor
. The first pilot bore generated
information about the distribution an d
density of blocks and boulders . A lot of deviations
and losses of drilling fluids happened ,
so the pilot bore had to be re-started again a
second time, until the optimal starting zon e
and angle and an optimal drilling path throug h
the block accumulations was found . Then th e
pilot bore of the first crossing needed one an d
a half day, the second pilot bore, two meters
parallel, was done in one day .
For the reaming process, a first enlarging ste p
was done with a 4" hole opener body wit h
8" hole opener cutters with TCI-Bits . Thi s
reaming needed 9 1/2 hours . For the secon d
crossing an additional reaming with 12" TC I
cutters needed 1 1/2 days. In 5 days, all drillin g
and reaming steps including pipe laying wer e
done and content customers looked for ne w
river crossing projects in this region .
HDD Rock drilling in nearly
2000 meters at Laax (CH )
In the region of the Glarn Alps, which are
reaching with the Tödi summit 3620 m ,
in eastern Switzerland, in the Graubünde n
(Grisons) villages of Laax and Flims winte r
sport activities are very well-known and th e
mountains above Laax and Flims are famou s
for their skying possibilities . More and more
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TRECNHLESS TECHNOLOG Y
Fig . 3 : Drilling through a mountain ridge in the Swiss Jura near Reigoldswi l
winter sport localities in the Alps install artificial
snow producing snow cannons .
Also in Laax, water pipes for a connectio n
between a water reservoir to snow cannon s
arrays had to be installed . A rock drilling wit h
334 m length under a summit-ridge for takin g
a 400 mm-waterpipe became necessary. Th e
starting point was 1940 m above sealevel ,
the aim point at 1934 m, so the inclination ,
which had to be realised, was 0,68 % . A
straight line with such low but exact inclination
under a maximum cover of rocks of 40 m
is a very pretentious task, which was fulfille d
by the Italian HDD drilling company Bianc o
in September 2006 in an optimal way. Th e
drilling specialist BIANCO used a Prime Drilling
75/50 HDD unit (Figure 2), witch was
equipped for the pilote bore with a 6 3/4 "-Mudmotor
with a 9 7/8" roller bit . The bore hole is
situated for 20 m in boulders and block material,
the main part with more than 310 m i s
in solid rocks of the hard helvetic limestones .
The bore hole was enlarged with a 23" hol e
opener, made by Prime Drilling. The pipe laying
into the borehole used a 17 1/2" front hol e
opener for Boing award of the pipe throug h
the bore . The drilling job was finished withou t
any complications in a very short time .
Lake crossing in the Allgä u
(Allgeau) Alps, SW Bavaria (G )
The Alpsee (see means Jake) is located 725 m
upon sealevel in the west of Immenstadt i n
the Allgäu Alps between the Lake Constanc e
and Tirol (Tyrol) . The mountains north of the
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Jake reach an altitude of 1100 m, south o f
the Jake more than 1800 m . The Alpsee itsel f
has an east-west length of about 4 km an d
a north-south extension of maximal 1100 m .
The depth of the Jake is maximal 24 m . Th e
geology beside and below the Alpsee is de-
termined by molasse sequences (Tertiary) ,
on the Jake ground moraine material is sedimented
.
The city of Immenstadt had the duty to buil t
a ring sewer system around the Jake, with
560 m gravity pipes, 9100 m pressure pipes ,
35 pumping stations and their necessary
equipment . From the pressure pipes, 2300 m
were pipes below the Jake ground, wherei n
the most pretentious task was a north-sout h
Jake crossing of 600 m length in the wester n
and smaller part of the Jake . The depth of th e
Alpsee is here 16 m, the pressure pipe ha d
to be positioned at minimum 3 m below th e
Take floor .
The city of Immenstadt assigned for this Jak e
crossing for the experienced company Ma x
Wild from Illerbachen . Max Wild used a Grundodrill
20 S HDD unit from Tracto-Technik an d
even a small boat for navigating of the dril l
head from the water level . The pilot bore wa s
done with a soft rock drill head, because th e
ground moraine and the following molass e
layers enabled this method . Boulders were
surrounded and a successful path was drille d
without interruption in one day and followin g
night. The first reaming step together with th e
pipe Iaying from the other side of the Alp Lak e
needed also one day and one night . The effective
Take crossing distance was 650 m, the
longest Jake crossing in the Alps, done wit h
a 20 t-drilling rig in an extreme short drillin g
time and with a very content and impressed
customer side .
Through the Swiss Jura
mountains near Reigoldswi l
Reigoldswil is situated in the canton of Basel -
Land and embedded in folded Jura mountain s
which reach the altitude of 900 to 1200 m . A
natural gas pipeline, existing since 1967, ha d
to be replaced and also deviated at the village
area of Rappertswil . The new segment of th e
steel pipeline was 900 m in length, now localised
further away from the next buildings . Th e
network owner, the Gasverbund Mittelland AG ,
decided to cross within a mountain ridge in a
length of 460 m . The mountain ridge "Bergli "
consists of a typical Upper Jurassic sequenc e
with hard limestone and week marls in frequently
changing horizons .
For realising the project in summer 2005 ,
first a small street up the mountain hillsid e
had to be constructed, for transporting th e
necessary 100 t-Prime Drilling HDD unit to
its starting place . The experienced drillin g
company Bohlen&Doyen from NW-Germany ,
owner of the 100 t-Prime Drilling unit, mad e
a pilot bore with a mudmotor, equipped wit h
a 250 mm roller bit (Figure 3) . The steerin g
was realised by an artificial magnet field at
the drilling area and with a navigation syste m
behind the bore head connected with a wir e
line inside the drill rods to the steering board
at the machine .
The drilling process in the Jurassic Iayer s
needed at lot of changements in the drilling
fluid regime, according to the strata dominance
in the bore hole . The whole drilling
fluid was recycled on site . The second working
step of the enlarging of the borehole with a
500 mm hole opener . The third step was th e
traction of the welded steel pipe with 273 m m
diameter into the borehole, which was fille d
with a enriched drilling fluid .
The job site was finished exactly in the determined
time, the customer side was ver y
content and even published reports on this
job site in Switzerland .
Horizontal drillings fo r
geological surveys of
tunneling projects in France ,
Italy and Austria (Montblan c
and Brenner/Brennero )
Beginning with the geological research fo r
the new Montblanc railway basis tunnel, Jon g
horizontal drillings, deviated from vertica l
starting places with vertical drilling rigs, fo r
the winning of core material from the futur e
zone of later tunnel escavating, came into
application . In the last years, the geologica l
research of future Brenner (o) basis tunne l

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needed kilometers of horizontal drillings i n
Austria and Italy .
Unfortunately, the method of drilling is classical,
with a derrick, with vertical equipment,
but with a defleetion in some hundre d
meters for going then horizontally in th e
relevant zone of future tunneling. The goo d
experiences with the receivable geologic Information
are so dense and so exact, tha t
for nearly all planned and agreed tunne l
projects in the Alps, horizontal survey drillings
will be asked for . So it is a good Chanc e
for the HDD drilling industry, going into thi s
market and to convince customers, usin g
HDD rigs in the future .
Results and chances
The described HDD applications in th e
mountains region of the Alps and thei r
foothills demonstrate, that even under ver y
rough and rigid topografic and geologic conditions
and circumstances, successful an d
even excellent HDD drillings are possible .
The market for HDD applications in the Alp s
will increase, because of more restrictive
laws for the environmental protection an d
because of more tunneling projects, whic h
will offer the chances in geological reseärc h
works by horizontal drillings and will offe r
chances in the renovation and improvemen t
of existing tunnels . They will need more security
infrastructure as there are fire protection
water mains, communication, steerin g
and sensor Gables, which can be installe d
by HDD works .
The environmental protection will require
much more HDD drillings for pipe laying s
in the mountains and therefore it is equal i f
water mains will be needed for feeding snow
cannons or hotels, if the pipes are for natura l
gas or for taking fiber optic Gables, if they ar e
for sewers or for electricity Gables, for illumination
or for rope railways .
Literatur e
[1]
Bayer, H .-J . (2006) : HDD Practice Handbook .-
191 p ., Essen : Vulkan-Verlag
Pioneers in Trenchiess since 196 2
industry
solid, reliable, powerful techni
for bares U, p,t0
13 Grundorm tt g i it~ t
TRENCHLESS TECHNOLOG Y
[2] Gasverbund Mittelland AG (2005) : Gemeind e
Reigoldswil – Umlegung der Erdgasleitung .
Projektbericht, 5 p ., Arlesheim, Switzerlan d
[3] Max Wild (2005) : Firmenpräsentation 5 0
Jahre Max Wild (inkl . Baustellenberichte) .
– Illerbachen-Berkheim, Germany
[4] TRACTUELL (2006) : Grundodrill 13X applicatio n
Author :
TRACTO-TECHNIK GmbH & Co. KG . RO .Box 4020 . D-57356 Lennestadt
Phone: +49-2723-808291 •Email : export@tracto-technik.tle . www.tracto-technik .com
in Slovenia – On the trail of Karl May .- S . 2 4
– 25, Tractuell 17/E – Magazine for Technik-
Technik customers, Lennestadt, German y
Dr. Hans-Joachim Baye r
New applications manager, Tracto -
Technik GmbH & Co KG ,
Lennestadt, Germany
Phone : +49(0)7025/84370 4
E-mail : hj-bayer@tracto-technik .d e