R. D. Fossey

Diajet Use in an Environmental Application

In order to treat and remediate ground contaminated with hazardous materials, long horizontal wells are often beneficial around the contaminated sites. While it is possible to drill and case these holes using existing technology, it is difficult and expensive to install perforated liners to give access to the formations. A procedure has been developed and is described wherein a DIAjet system is used to feed through the drill pipe and to perforate this at regular intervals, thereby allowing access to the formation along the length of the horizontal well. The relative benefits of this approach and indicators of its performance are discussed.

Low Pressure Abrasive Waterjet Use for Precision Drilling and Cutting of Rock

Construction of a second theater underground at the Gateway Arch in St. Louis required a quiet, non-intrusive means of rock removal, capable of cutting the vertical walls of the theater down to a depth of 4.5 meters, within a vertical accuracy of 2.5 cm. A low pressure (35 MPa) abrasive laden waterjet was developed for this; and, also modified as an abrasive waterjet drill to emplace 25 mm diameter resin-bonded rock bolts in the rock walls.

Neutralization of potential land mine hazards by abrasive waterjet use

A method of neutralizing landmines in which the integrity of the surrounding terrain is retained is herein described. High pressure waterjets which can be used to detect the presence of landmines can then be used to remove the soil and other cover in a plane immediately adjacent to and around the mine so that the side of the mine can be visually inspected through a remote television camera. At that time the flow of water is channeled through a line in which small particles of sand are added to the waterjet which is at a pressure of between 3,000 and 10,000 psi depending on the device which is used. Jet flow rates are on the order of 5 gpm depending on the nozzle configuration used. By bringing this abrasive stream in along a lateral plane through the mine it is possible to intersect, and neutralize, the fusing systems most likely to be used to initiate the charge, in a single pass. At higher flow rates, as the cut is made the jet will generate significant turbulence in the mine body, sufficient to remove a considerable quantity of the explosive which is resident within the mine at the same time as the mine is being dissected. The precision of cut achievable is shown by the longitudinal cutting into two parts of live detonators, as well as representative mine bodies.

The Feasibility of Commercial Diajet Use (A Case Study)

The paper consists of fiscal evaluations of DIAjet use in a commercial environment. A DIAjet system was used by a small contractor to cut a 21 cm thick reinforced concrete wall in an existing high-rise residential complex. Comparisons and contrast of DIAjet cutting and conventional methods of masonry removal are discussed. An economic evaluation from the viewpoint of the contractor, as well as environmental concerns, are discussed. Improvements required in the technology are examined that will allow it to become an everyday tool from a small contractor point of view.