Prairie Dog Boring Equipment
Boring with all Prairie Dog machines is simple. The basic thing to remember is that you need proper setup. Watch the video, read your instructions thoroughly, understand what the equipment is engineered to do and you can bore a hole easily and successfully.
Simply dig a small trench, align the drill stem in the trench and connect your fluid source to the machine. Then install your drill stem and pilot bit, and turn on the water.
Start the bit rotating and advance the machine forward. Add drill stem until you come out at your target point. Then remove the pilot bit, replace it with the desired size of backreamer and reverse through the pilot hole.
Ditch the Missiles
Missiles can end up anywhere but where you aim them including the middle of the road. Soil conditions dictate whether they can be used at all. Missiles can get stuck or lost altogether along with a significant investment which leads you to making a major decision. Dig it out and tear up what you were trying to avoid disturbing in the first place or leave it there and buy another one. This won’t happen with a Prairie Dog Machine. Our machines will work in a variety of soil conditions and just by design accuracy is much better.
Watch the video and see the manual for total instructions.
How does it work?
All Prairie Dog Boring Machines work by turning a carbide tipped pilot bit to bore the initial “pilot” hole. Setup depends on the model of machine being used but they all are designed to drill a straight-line hole. Water is used to flush the hole as the bit is cutting.
If the original hole needs to be made larger the appropriate sized back reamer can be pulled back through the hole cutting in much the same way as the pilot bit.
You should only backream one time to the size you need. In other words if you need a 10″ hole you should bore the pilot hole and then expand the hole with a 10″ backreamer. Some customers find that stacking backreamers on the same drill string helps speed up the cutting or mix a better slurry so they may have a 4″, 8″ and 10″ backreamer, for instance, all stacked together on the one backreaming process. Soil conditions may dictate whether stacking helps or hinders the process. A little experience trying different methods will be invaluable.
How Much water does it take?
A 2″ pilot hole 40′ long will usually take somewhere between 30 and 50 gallons in optimum conditions. This water needs to be supplied at around 40-50 psi or standard municipal water pressure and flow. The machines come standard with a garden hose connection but can be equipped with other connections if needed or easily adapted in the field.
How long does it take?
The time it takes to complete a bore will depend largely on the soil conditions. However, in good conditions that same 2″ x 40′ bore shouldn’t take more than about 20 – 30 minutes to complete depending on model. A 4″ – 6″ back reamer will take about the same amount of time. You can add about 20% to the time it takes to back ream a hole for each 2″ increment you increase the finished hole size. These are “rule of thumb” estimates in good conditions.
Doesn’t it make a mess?
Not as much as you might expect. The water combines with the substrate to create a slurry. This slurry usually stays by the entrance of the hole. Any additional water runoff can be contained by digging a small sump and either allowed to soak into the ground or pumped off. The slurry that is left in the hole serves as a lubricant when inserting the casing, cable, pipe or conduit.
Our machines turn the bit at the right combination of speed and power. Enough power to bore through the toughest conditions but fast enough to thoroughly mix the water and soil into the proper slurry.
Will it bore through rock?
Yes, Carbide tipped bits and Back Reamers allow the machine to handle boring through the toughest conditions. There are many different types of rock though. The amount of time it takes to bore depends on how hard the rock is.
I have a lot of sand in my area. Can I still bore with a Prairie Dog without cave ins?
Yes, you can. A mixture of bentonite clay (drilling mud) can be substituted for the plain water. This drilling mud will help stabilize the hole in granular soils. Due to the nature of sand and it’s larger particles it doesn’t have a lot of cohesion. Water can easily get in between the particles and weigh the sand down causing a hole to collapse. Bentonite works by sealing off the sand so that it doesn’t absorb the water and get weighed down. Bentonite clay is a naturally occuring soil. It must be thoroughly mixed with water in a tank but doesn’t need to be a particularly heavy mud for boring purposes. A mixture slightly thicker than water can be pumped with a standard centrifugal pump and is sufficient for sealing purposes when boring.
What about really sticky Clay?
Clay can be especially tricky for any boring machine. The soil may not mix well in water to easily exit the hole or the clay surrounding the hole may swell
and constrict the boring rod. Fortunately there are easy solutions. Our bits turn at an optimum speed to shear the clay for the best mixing with water to form
a proper slurry when possible. There are still some clays that resist this shearing and may need a little help. The introduction of relatively inexpensive clay inhibitors
acts as a kind of detergent which allows the clay particles to separate. The inhibitors also prevent the absorption of water which prevents swelling.
These clay inhibitors can be introduced into the water system in a number of ways.