Betti I Tunneling Machine Patent Number: 03345108

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The Betti I was manufactured at the Hughes Tool Company subsidiary plant, Hugh B. Williams Manufacturing of Dallas, Texas for Fenix & Scisson of Tulsa, Oklahoma for drilling a two mile long irrigation tunnel providing water from the Navajo Reservoir near Bloomfield, New Mexico to the Navajo Indian Reservation.

The Betti I was designed, produced and tested in the Dallas, Texas Plant. Completion of the project required less than one year. The project was designed and developed by Hollis Travis, Elmer Newman, John Vischer, Walter McFarland, Joe Glass and Harold Parker with assistance from Joe Kelly and various groups at the Hughes plants. The complete testing, the machine was disassembled into its major components and shipped by truck to the tunnel site near Bloomfield, New Mexico. (See photo: HBWEngineers01.jpg)

The "Betti I" was one of the largest tunneling machines ever produced for drilling hard rock formations. Hughes Aircraft discovered and developed the ruby laser and it was first used on the Betti I's guidance system. This was the first commercial use of the laser beam, which resulted in a very efficient method of determining the direction of the tunneling machines path and enabled the operators to instantaneously change the position of the rotating boring head to correct any misalignment in direction.

The operators compartment was a large comfortable module attached to the side of the machine. The compartment was fully insulated and air conditioned and the console was designed to give the operator complete control of the drilling operations.

The drilling head had over twenty saddle-type cutters mounted in concentric patterns to cover the entire area, to drill tunnels ranging in size between twenty and twenty-two feet in diameter. Hughes Tool Company had developed these saddle cutters for similar applications where large diameter holes were to be drilled in hard formations.

It was determined that the cost savings from the production of a straight, smooth and concentrically bored tunnel would offset the cost of building a special machine for the Navajo Project since experience had clearly shown that a considerable smaller amount of concrete would be required to produce the lining when the tunnel was produced by boring.

Previously, large tunnels were produced by drilling small holes into the very hard rock formations where charges of explosives were planted. Many series of these uncontrolled explosions eventually produced a tunnel, but often resulted in huge irregular voids in the tunnel walls. It was necessary to fill these voids with concrete when the tunnel was completed and lined. It was difficult to determine the quantity of concrete required to produce the finished tunnel and thus production costs were difficult to control.

The unique features of the Betti I allowed both the angular and parallel motion of the rotating drill head to be positioned while in operaion so any deviation in the line and grade of the bored hole could be easily corrected. U.S. Patent 3,345,108 was issued covering this unique design concept.

The drilling crews would sometimes wager on which crew could be nearest to the required line and grade at the end of each shift. Frequently, the variations in the bored tunnel all would be within one-quarter inch of being perfectly aligned to the desired course.

A laser was set up at the tunnel entrance on a transit tripod and its beam directed to the specific line and grade of the tunnel. The beam of red light from the laser activated light sensors mounted on the side of the machine near the drilling head. The results were sent electronically to a similar readout panel mounted in the operator's compartment, so the operator could immediately see any deviation in the line or grade and immediately correct for misalignment. (See photo: BettiLaserROP.jpg)

Drilling of the tunnel was fast and efficient. Fenix & Scisson installed a California Switch to enable rail cars to pull up behind the tunneling machine while it was drilling. The drilled material was picked up by buckets on the rotating cutter head and dumped on to a conveyer on top of the machine. This enabled the drilling crews to be able to remove a fully loaded rail car while bringing in an empty car and operate continuously without interupting the drilling operations. Frequently the operator of the tunneling machine would slow down from the maximum of five feet per hour advance rate to allow the material removal crew to catch up.

During the course of drilling the tunnel, sections of softer formations were occasionally encountered and the soft material caved in on top of the machine. No personel were ever at risk, but after a large cave in it was necessary to halt production and clean out the material that had fallen before drilling operations could be continued. After riding atop the machine, sitting just behind the rotating cutter head for almost a full day with Sid Scisson, we devised a method of manually installing heavy oak boards over the top section of the tunnel immediately behind the rotating cutter head to prevent future caveins. Ring beams were then installed under the heavy boards to keep these boards in place until the tunnel was complete and the concrete lining could be poured over them.