In directional drilling,
each bore presents a new and unique challenge. Soil conditions can change from
one extreme to the other within the same bore. Often, the bore path is
congested with existing underground utilities that must be avoided. Overhead
power lines, microwave towers, traffic light loops, and steel reinforcing in
concrete are just a few examples of items that can interfere with locating the
drill head. With all the potential pitfalls, the ability to successfully complete
a bore often hinges on advance planning.
In this chapter, we will
discuss planning the bore as it pertains to the drilling contractor. There are
special planning considerations for environmental remediation work which would
normally be performed by an environmental engineer.
Existing Utilities
One of the first
considerations in planning the bore should be the location of underground
utilities. In the United States there are a number of companies
that provide this service to the contractor. They are generally referred to as
"One Call" notification services. One Call notification services vary
somewhat from state to state since there is currently no uniform federal law.
However, they all require notification, generally 48 -72 hours depending on the
state, before any boring, trenching, or excavating can begin. They will locate
all known utilities along the proposed bore path. However, they typically do
not provide depth information. It is the contractors responsibility to expose
(pot hole) every utility that intersects the bore path to determine the exact
location. Remember, pot holing is the only reliable method for determining
where the existing utility is located.
At the end of this chapter
you'll find a directory of One Call services. The caller will be asked to
provide the following information:
- Name of county and township or municipality
- Section number
- Street address
- Type of work
- Name of caller
- Title of caller
- Start date and time
- Best time to call back
- Contractor
- Contractor's address and phone number
Once this information is
provided, the caller will be given a job number. This number is proof that One
Call was notified and it should be retained for future reference in the event
that a problem arises.
The uniform color code for
marking underground utility lines is as follows:
RED |
Electric |
YELLOW |
Gas -- Oil -- CATV |
ORANGE |
Communication -- CATV |
BLUE |
Water |
GREEN |
Sewer |
PINK |
Temporary survey markings |
WHITE |
Proposal excavation |
Most of the world does not
have the benefit of a One Call service, and the contractor is directly
responsible for all locates. Quite often, maps containing information on the
location of underground utilities are not available. In these cases, it is even
more important that time is spent reading the job site to determine the
location of all utilities. Items to look for that might indicate a buried
utility could include:
- A ditch line depression in the landscape.
- A building with lights that has no wires coming in
overhead.
- A patch in the blacktop or concrete street. Any pole
with electric wires extending down into the ground.
- Transformer boxes.
- Manhole covers.
- Water or gas shut-off valves.
While checking the site for
utilities, you must ask yourself, "How was this utility installed?"
If it was plowed or trenched, there is a good chance that the depth will be
fairly consistent. On the other hand, if it was installed with a backhoe, the
depth could vary considerably.
Machine Placement
There are several items
that need to be considered when determining machine placement. The major factor
will be the physical limitations of the site itself. There has to be enough
room to set the machine up so that maximum depth can be obtained without
exceeding the bend radius of the drill pipe. (See Drill Pipe Specifications
chart at end of chapter.) There also has to be enough room to accommodate the
product being installed. If there are any variations in the elevation from one
end of the bore path to the other, it is better to drill downhill. This will
help to keep the drilling fluid in the hole instead of having it run out by the
machine.

To determine the minimum
set-back distance required to obtain a specter depth, the desired depth and the
rack angle of the machine must be known. Dividing the rise (depth) by the rack
angle will calculate the minimum set-back distance required to obtain the
desired depth. This assumes a straight line with no steering corrections. If
the drill head needs to be level at the desired depth, then it will be
necessary to add approximately 30 feet to the set-back distance. The footage
required to level the drill head will vary depending on the bend radius of the
drill pipe that is being used.
Two other formulas that can
be useful when determining the proper rack placement are:
RISE / RUN = ANGLE and RUN X ANGLE = RISE
Bore Path
Interference
Overhead power lines,
traffic light loops, and steel reinforcing in concrete are just a few examples
of items that can interfere with locating the drill head. Metal buildings,
invisible dog fence, and automobiles with electronic fuel injection can also
cause interference. Interference with the locating equipment can cause serious
problems and can prevent a bore from being completed. By checking for
interference along the bore path before any drilling begins, it might be
possible to eliminate the problem. If the problem can not be eliminated, it
will be easier to deal with by just knowing that there will be a problem in a
certain area.
To check for interference,
walk the bore path with the receiver before powering up the sonde. Watch the
signal strength on the receiver. Any high signals along the bore path could
indicate a problem area. It is advised to mark these areas so the crew member
doing the locating will be prepared for the problem.
Determining Grade
When planning the bore, it
is a good idea to determine the grade of the topography of the proposed bore
path. This can be quite helpful when trying to maintain a constant depth. This
is easily accomplished by laying the sonde on the ground, taking a pitch
reading with the receiver, and recording the information. Repeat this process
any place where the slope of the ground changes. Once the maximum depth is
obtained, it can be maintained by keeping the pitch of the drill head
consistent with the slope of the surface.
Mud Requirements
A well-planned bore
includes knowing how much drilling fluid will be required. This will vary from
job to job depending on soil conditions and the size of the back reamer being
used. A good rule of thumb for estimating the amount needed is to take the
diameter of the back reamer squared and divide that number by 24.5. The answer
will be the number of gallons per foot of bore. We will cover this in more
detail in Chapter 3, Drilling Fluids and Back Reaming.
Summary
The bore planner on the
following page can prove useful not only for planning, but also for recording
the bore as built. The most important part of the planning process is to supply
a list of emergency phone numbers to the crew. HDD is safe, but just like any
other occupation, accidents can occur. Having these phone numbers available
could save a life. Some other items that need to be considered in the planning
stage are:
- What type of product is to be installed? Is it on hand?
- What size and type of back reamer is needed? Will
prereaming be necessary
- Are batteries for the locator fully charged? Are new
batteries on hand for the sonde? What about the batteries for the
walkie-talkies?
- Is there plenty of thread compound? How about a
paintbrush for applying the thread compound?
- Everyone on the crew should have their own tasks that
they are responsible for. This will speed up the drilling process
considerably.
- Make sure that the proper safety equipment is on hand
and ready for use.
By planning the bore and
having everything ready, the chance of performing a successful bore increases
dramatically. It is also more professional.
Bore Planner
_________________________________
|
___________________________________
|
Customer |
Date |
_________________________________
|
___________________________________
|
Address |
Job # |
_________________________________
|
___________________________________
|
City, State, ZIP |
Contact Person |
_________________________________
|
___________________________________
|
Phone |
Phone |
Location of bore_________________________________________________________________ |
Type and size of product to be installed_______________________________________________ |
Estimated Length of bore__________________________________________________________ |
________Water |
_______Paint Brush |
________Bentonite |
_______Location Flags |
________Polymer |
_______Duck Bills |
________Batteries for Locator |
_______Back Reamers |
________Thread Compound |
|
Ground Conditions
|
|
|
|
|
|
__ Gravel |
__ Loam |
__ Hardpan |
|
|
|
Reamer
|
|
|
Size ________ |
Type ________ |
Preream Yes/No |
Emergency Phone Numbers:
|
|
Ambulance |
_______________________________________ |
Electric company |
_______________________________________ |
Gas company |
_______________________________________ |
Phone company |
_______________________________________ |
Water company |
_______________________________________ |
Sanitation Department |
_______________________________________ |
One Call locating service
contacted on_____/______/______By________________________
Name of person contracted:_____________________________________________________
Length
|
Depth
|
Pitch
|
Steering
|
Length
|
Depth
|
Pitch
|
Steering
|
Length
|
Depth
|
Pitch
|
Steering
|
5
|
|
|
|
175
|
|
|
|
345
|
|
|
|
10
|
|
|
|
180
|
|
|
|
350
|
|
|
|
15
|
|
|
|
185
|
|
|
|
355
|
|
|
|
20
|
|
|
|
190
|
|
|
|
360
|
|
|
|
25
|
|
|
|
195
|
|
|
|
365
|
|
|
|
30
|
|
|
|
200
|
|
|
|
370
|
|
|
|
35
|
|
|
|
205
|
|
|
|
375
|
|
|
|
40
|
|
|
|
210
|
|
|
|
380
|
|
|
|
45
|
|
|
|
215
|
|
|
|
385
|
|
|
|
50
|
|
|
|
220
|
|
|
|
390
|
|
|
|
55
|
|
|
|
225
|
|
|
|
395
|
|
|
|
60
|
|
|
|
230
|
|
|
|
400
|
|
|
|
65
|
|
|
|
235
|
|
|
|
405
|
|
|
|
70
|
|
|
|
240
|
|
|
|
410
|
|
|
|
75
|
|
|
|
245
|
|
|
|
415
|
|
|
|
80
|
|
|
|
250
|
|
|
|
420
|
|
|
|
85
|
|
|
|
255
|
|
|
|
425
|
|
|
|
90
|
|
|
|
260
|
|
|
|
430
|
|
|
|
95
|
|
|
|
265
|
|
|
|
435
|
|
|
|
100
|
|
|
|
270
|
|
|
|
440
|
|
|
|
105
|
|
|
|
275
|
|
|
|
445
|
|
|
|
110
|
|
|
|
280
|
|
|
|
450
|
|
|
|
115
|
|
|
|
285
|
|
|
|
455
|
|
|
|
120
|
|
|
|
290
|
|
|
|
460
|
|
|
|
125
|
|
|
|
295
|
|
|
|
465
|
|
|
|
130
|
|
|
|
300
|
|
|
|
470
|
|
|
|
135
|
|
|
|
305
|
|
|
|
475
|
|
|
|
140
|
|
|
|
310
|
|
|
|
480
|
|
|
|
145
|
|
|
|
315
|
|
|
|
485
|
|
|
|
150
|
|
|
|
320
|
|
|
|
490
|
|
|
|
155
|
|
|
|
325
|
|
|
|
495
|
|
|
|
160
|
|
|
|
330
|
|
|
|
500
|
|
|
|
165
|
|
|
|
335
|
|
|
|
505
|
|
|
|
170
|
|
|
|
340
|
|
|
|
510
|
|
|
|
One-Call Directory
ALABAMA Alabama Line Location Center 1-800-292-8525
ALASKA Locate Call Center of Alaska, Inc. 1-907-278-3121
ARIZONA Arizona Blue Stake, Inc.
1-800-782-5348
ARKANSAS Arkansas One Call System, Inc.
1-800-782-5348
CALIFORNIA
Underground Service Alert
North 1-800-227-2600
Underground Service Alert
South 1-800-227-2600
COLORADO
Utility Notification Center of Colorado 1-800-922-1987
CONNECTICUT
Call Before You Dig
1-800-922-4455
DELAWARE
Miss Utility of Delmarva
1-800-282-8555
FLORIDA
Sunshine State One Call of Florida, Inc. 1-800-432-4770
GEORGIA
Utilities Protection
Center, Inc. 1-800-282-7411
IDAHO
Dig Line 1-800-342-1585
Palouse Empire Underground
Coordinating Council 1-800-822-1974
Kootenai County Utility Coordinating Council 1-800-428-4950
Utilities Underground
Location Center 1-800-424-5555
One Call Concepts -Idaho 1-800-626-4950
Shoshone County One Call 1-800-398-3285
ILLINOIS
Julie, Inc. 1-800-892-0123
Chicago: Digger 1-312-744-7000
INDIANA
IN Underground Plant
Protection Services, Inc. 1-800-382-5544
IOWA
Underground Plant Location
Service, Inc. 1-800-292-8989
KANSAS
Kansas One Call Center 1-800-DIG-SAFE
KENTUCKY
Kentucky Underground Protection, Inc.
1-800-752-6007
LOUISIANA
Dottie System, Inc.
1-800-272-3020
MAINE
Dig Safe ---- Maine 1-888-344-7233
MARYLAND
Miss Utility of Delmarva
1-800-282-8555
Miss Utility 1-800-257-7777
MASSACHUSETTS
MASSACHESETTS
Dig Safe Massachusetts 1-888-344-7233
MICHIGAN
Miss Dig Utility
Communication System 1-800-482-7171
MINNESOTA
Gopher State One Call 1-800-252-1166
MISSISSIPPI
Mississippi One Call System, Inc. 1-800-227-6477
MISSOURI
Missouri One Call System, Inc.
1-800-344-7483
MONTANA
Utilities Underground
Location Center 1-800-424-5555
Montana One Call 1-800-551-8344
NEBRASKA
Diggers Hotline of Nebraska 1-800-331-5666
NEVADA
Underground Service Alert
of NV 1-800-227-2600
NEW
HAMPSHIRE
Dig Safe -- New Hampshire
1-888-344-7233
NEW JERSEY
Garden State Underground Line Locating Service
1-800-272-1000
NEW
MEXICO
New
Mexico One Call System, Inc. 1-800-321-ALERT
NEW
YORK
Underground Facility
Protection Organization 1-800-962-7962
New
York City Long Island One Call Center 1-800-272-4480
NORTH
CAROLINA
North
Carolina One Call Center 1-800-632-4949
NORTH
DAKOTA
Utilities Underground
Location Center 1-800-454-5555
OHIO
Ohio Utilities Protection Service
1-800-362-2764
OKLAHOMA
Call Okie 1-800-522-6543
OREGON
Utility's Underground
Location Center 1-800-424-5555
Douglas Utility's Coordinating Council
1-503-673-6676
Josephine Utility's
Coordinating Council 1-503-476-6676
Utility's Notification
Center 1-800-332-2344
Rogue Basin Utility Coordinating Council
1-503-779-6676
PENNSYLVANIA
Pennsylvania One Call System, Inc.
1-800-242-1776
RHODE ISLAND
Dig Safe -- Rhode Island 1-888-344-7233
SOUTH
CAROLINA
Palmetto Utility Protection
Service, Inc. 1-800-922-0983
SOUTH
DAKOTA
South
Dakota One Call 1-800-781-7474
TENNESSEE
Tennessee One Call System 1-800-351-1111
TEXAS
Lone Star Notification
Center 1-800-669-8344
Texas Excavation Safety System
1-800-344-8377
Texas One Call System 1-800-245-4545
UTAH
Blue Stakes Location Center
1-800-662-4111
VERMONT
Dig Safe Vermont 1-888-344-7233
VIRGINIA
Miss Utility of Virginia 1-800-522-7001
Miss Utility 1-800-257-7777
Miss Utility of Delmarva
1-800-441-8355
WASHINGTON
Utilities Notification
Center 1-800-332-2344
Grays
Harbor & Pacific County Utility Coordinating Council
1-206-532-3550
Utilities Underground
Location Center 1-800-424-5555
Chelan-Douglas Utility
Coord Council 1-509-663-6111
Upper Yakima County Underground Utilities Council
1-800-553-4344
Inland Empire Utility Coordinating Council
1-509-456-8000
Utilities Council of Cowlitz County 1-360-425-2506
Palouse Empire Utility
Cord. Council 1-800-822-1974
WASHINGTON, DISTRICT OF COLUMBIA
Miss Utility 1-800-257-7777
WEST
VIRGINIA
Miss Utility of West Virginia, Inc. 1-800-245-4848
WISCONSIN
Diggers Hotline, Inc.
1-800-242-8511
WYOMING
Wyoming One Call 1-800-348-1030
West Park Utility Coordinating Council
1-307-587-4800
Converse County Coordinating Council 1-800-562-5561
Fremont County Utility Coord Council
1-800-489-8023
Central Wyoming Utilities Coordinating Council
1-800-759-8035
Albany County Utility Coordinating Council 1-307-742-3615
Southeast
WY Utility Coordinating Council 1-307-638-6666
Southwest
Wyoming
One Call 1-307-362-8888
Utilities Underground
Location Center 1-800-454-5555
Carbon County Utility Coordinating Council 1-307-324-6666
Call-In Dig-In Safety
Council 1-307-682-9811
CANADA
Alberta: Alberta One Call Location Corp.
1-800-242-3447
British
Columbia: BC One Call 1-800-474-6886
Ontario: Ontario One Call Centre Ltd.
1-800-400-2255 or 905-709-1717
Ontario: Waterloo Region Bud System 1800-265-2288
Ontario: Call "Bud"
1-905-527-7977