Unique instrumentation is often required to adapt RIM techniques to special geologies and geometries, and for non-standard mining and industrial applications. Therefore SGM advances the field services capabilities of its RIM-6 technologies by development and fabrication of specialized adaptive and deployment technologies in support of RIM-6. For unusual or particularly difficult job requirements, SGM has the ability to design and build custom RIM systems and accessories for client projects and imaging objectives.
The specialty systems developed by SGM allow the Borehole and In-Mine technology discussed thus far to be adapted and deployed for non-standard applications. A brief discussion of some recent “Specialty Systems” follows.
The H-Reel System is designed for areas where powered hoists are not convenient or necessary, where power is unavailable or in instances where the powered hoists are not permitted. The H-Reel System consists of two spools of fiber optic cable and two spools of 1/8″ Amsteel Blue line. The function of the Amsteel line is to assist with “non-gravity” surveys where the borehole dip is less than about 20 degrees (i.e. sub horizontal).
The H-Reel system is compatible with all RIM-6 borehole battery packs, electronics sections, and antennas. Each H-Reel can function as a transmitter or receiver depending on the borehole electronics attached. Each fiber optic spool contains 160 meters (approximately 520 feet) of fiber optic cable, and a fiber optic probe section. Internal to the spool is a bluetooth modem for wireless communication to a PDA, a battery, and a battery charging port. The H-Reel can work in conjunction with another H-Reel, H-Link, In-Mine handheld system, or any of the RIM-6 hoist systems. Therefore, the H-Reel system is a “supplemental” accessory for any non-standard underground borehole project with remote, shallow, or difficult borehole conditions.
Amsteel Blue cable is a steel cable replacement product chosen for its light weight, low friction, high strength, and low-stretch qualities. The breaking strength of 1/8″ Amsteel Blue cable is listed by the manufacturer as 2,300 lbs (1000kgs).
Note: Although commonly referred to as Amsteel Blue, some RIM-6 systems may use alternate colors depending on application needs and product availability.
As standard, imaging surveys can only be accomplished using a complete borehole RIM imaging system, including a transmitter (TX) unit and a receiver (RX) unit. Thus the goal of the H-Reel System is to deploy one or more systems in one, or both, of these roles. The borehole probe systems (TX or RX) will include standard stainless steel or aluminum tube enclosures and stainless or non-metallic end-adaptors (probe interconnects). And as usual, the magnetic-dipoles use ferrite-core antennas and fiberglass composite housings.
In addition to the H-Reel spooling components, two other items are required for operation of the H-Reel System. A borehole collar is used to protect the fiber optic cable as it goes down the hole, and to keep it aligned in the center of the hole casing or lining. The large diameter Delrin wheel is for fiber optic cable, while the small diameter wheel is used only for Amsteel Blue line.
The collar base is equipped with a series of adjustable tightening bolts so that the collar can be used on a variety of well casing or lining styles and diameters. And finally, every H-Reel and H-Link system requires the use of a PDA as a user interface and system control. In this configuration, the borehole probes are operated as a pseudo-In-Mine system.
The H-Link system is designed for instances in which minimal weight and maximum portability are desired, where access is limited, and where only a small amount of cable is needed. For instance the H-Link would be the system of choice in very shallow drilled holes where a partially stationary source is required, or for use in roof-bolt holes or various test holes. Like the H-Reel System, the H-Link System is designed to use standard “Borehole” probes in a manual “In-Mine” convention, independent of a large electric hoisting system. However the H-Link has very short electrical cables instead of fiber-optic cables so their length must be minimized to reduce the incidence of transmitted signal coupling on the cables.
One other variation with the R-Link System is the downhole assembly does not require a probe battery section since probe power originates in the battery enclosure. Thus data can be collected at more shallow depths under controlled spatial positioning. The H-Link is stored and transported in a durable, weather-sealed travel case. The H-Link system consists of two H-Link boxes, two comm/power cables with short fiberglass probe sections, and a carry case.
The H-Link system is compatible with all RIM-6 borehole electronics sections and antennas (again, no probe battery packs are required). Each H-Link can function as a transmitter or receiver depending on the borehole electronics attached. Each comm-power cable is roughly 14 meters long (approximately 45 feet). Internal to the battery enclosure is a bluetooth modem for wireless communication to a PDA, a battery, and a battery charging port. The H-Link can work in conjunction with any other H-Reel, H-Link, In-Mine handheld system, or any of the RIM-6 hoist systems. Therefore, the H-Link system continues to serve as an accessory for any non-standard shallow-borehole project, but can also be used outside of the borehole with the probe sections in direct contact with the imaged geology. One example of a borehole application of H-Link would be imaging between ROOF-BOLT holes. And one example of a non-borehole application of H-Link would be imaging between rock faces in an outcrop or highwall.
In general, the most common applications for both the H-Reel and H-Link are as fixed or limited-movement transmitter sources for significantly more mobile hoist-powered receiver ray path generation.
Sub-Horizontal RIM Deployment Methods
For boreholes with dip of less than -20 degrees (or even +dip up into the rib or roof), it is necessary to utilize one or more non-gravity-dependant “Probe Locomotion Options”. Historically, RIM probes were pushed into the borehole with long rods and then pulled back on their own cable. While not necessarily a bad idea, there are better was to collect data in sub-horizontal boreholes that allow more accurate, repeatable and high-volume data sets to be collected. The principle method is to use a second cable to pull the probe into the hole in conjunction with an End-of-Hole (EOH) anchor and pulley system. The second method is to push the probe down to EOH with water pressure. These two methods are described here.
Pull Cord “Pull-Down”
BOREHOLE IS EITHER LINED OR UN-LINED WITH PVC CASING, BUT BOTTOM-PULLEY MUST BE PRE-ANCHORED IN THE CASING, OR PUSHED DOWN WITH WATER PRESSURE.
Probe moves to End-Of-Hole on Pull-Cord (pulley assembly anchored at bottom).
Probe moves to Top-Of-Hole on Main Fiber-Optic Cable
Both the Main Cable and Pull-Cord are driven with RIM Hoist Winch Motor.
Water Pressure “Push-Down”
BOREHOLE IS LINED WITH FLUSH-JOINT PVC BY DRILLERS, SLOTTED AT BOTTOM FOR WATER EXCAPE.
Probe moves to End-Of-Hole by low-pressure water (probe-end forms sealed piston).
Probe moves to Top-Of-Hole on Main Fiber-Optic Cable. Pressure and Water Level controlled at collar by a provided Water-Coupler and accessories. System requires water source with a minimum pressure or only 10 to 20 psi.
The Water-Pressure Push-Down method can be used to locomotive the probe or the EOH anchor assembly. The principle Specialty System involves a custom built WATER-COUPLER and Pully System. The water couple is designed to fasten to the borehole pipe, collar, or open-hole adapter. The Coupler and Pulley assemblies allows water to be directed and controlled into the borehole or casing while simultaneously sealing and guiding the multiple cables for any device being propelled down the hole under water pressure. The Water-Coupler and Pulley assembly is then left on the borehole for the duration of the data collection.