In-Mine RIM 6
General RIM In-Mine System Description
The In-Mine RIM-6 survey equipment (IM) is man-portable and consists of receiver units (RX) and transmitter units (TX); all are currently non-permissible. During operation, the transmitter must be used on one side of the area-of-interest, and the receivers on the other side. The geology between the two units is imaged (transmission methodology). For longwall mapping, the TX in the maingate entry (beltway, intake) of the longwall block and the receivers must be used in the tailgate entry (return). Please note, a permissible version of RIM-6 is planned for late 2015. This approval will be for the receiver only (return entry). The transmitter (belt entry) will continue to be non-permissible.
The In-Mine RIM-6 instrumentation operates at discrete frequencies between 22-kHz and 1.2-MHz. Typically, the frequency used within a specific site geology is the highest possible given the distance range of the signal in the coal seam and panel width. Once the optimal frequency is determined, that single frequency is used for all radio-mapping at that particular site-geology and survey-scope. The TX unit broadcasts a continuous-wave radio signal to the RX units at a fixed wavelength and fixed radiated power level. The TX and RX units are not connected by any type of cable or wire. An In-Mine receiver unit is shown in underground operation in the following photo. The radio-frequency electronics are housed in the loop antenna and belt-mounted pouch. The display computer is a wireless Pocket PC (PDA) carried by the operator.
The photos below show the complete In-Mine RIM-6 System as prepared for underground deployment. The minimum amount of equipment necessary for an in-mine survey includes:
Two or more loop antennas
One IMT travel case
One IMR travel case
Two IM-PDA cases
One Charger case (surface only)
RIM-6 In-Mine Transmitter (IMT)
The photo below shows the complete In-Mine RIM-6 Transmitter System (IMT) as a collection of individual components. The system consists of an air-core magnetic dipole loop antenna, external control box (electronics and battery), fiberglass monopole, and a PDA control computer. The IMT system can be used anywhere as a radio-wave source for the creation of ray path through the imaged geology. For longwall mapping, the IMT system is typically used in the beltway entry since it is not susceptible to interference problems with metallic structure or power cables. The IMT is a light-weight device that can operate for at least 6 hours on its internal batteries. Antenna power is typically 10 to 50 watts depending on frequency output.
RIM-6 In-Mine Transmitter components: (A) wireless computer (PDA), (B) antenna loop, (C) electronics and battery module, and (D) fiberglass monopole.
The external electronics are housed within a plastic enclosure which is carried by the operator in a shoulder bag or belt pouch. The IMT electronics are connected to the loop antenna via a specialized multi-conductor cable and the electronics are powered by an internal battery. The separate IMT-PDA has a 3.3 AHr battery (5 VDC) and ruggedized case for use underground. The IMT, travel cases, and antenna are shown (two IMT units per case). Each unit consists of durable lockable plastic cases with hinges, latches, and handles. The only exposed socket or port is the receptacle for the loop antenna cable. The only user controls on this box are a single ON-OFF switch and indicator light.
RIM-6 In-Mine Receiver (RX)
The photo below shows the complete In-Mine RIM-6 Receiver System (IMR) as a collection of individual components. The system consists of a magnetic dipole loop antenna, external electronics and battery module, fiberglass monopole, and a PDA control computer. The IMR system must be used in areas where electrical interference levels (RFI and EMI) are minimized. These interference sources are typically communication and power-line noise, but radiated noise from electric motors and power transformers can be incredibly high for the ultra-sensitive RIM-6 receiver. For longwall mapping and other underground applications, the IMR system is typically used in the return entry since it typically lacks large metallic structures and power or communication cables.
RIM-6 In-Mine Transmitter components: (A) wireless computer, (B) antenna loop, (C) electronics and battery module, and (D) fiberglass monopole.
Like the IMT, the IMR is a light-weight device that can operate for at least 6 hours on its internal batteries. The IMR unit does not typically radiate power but it does have a very low-power calibration-transmitter built internal to the receiver loop for characterizing antenna performance and tuning efficiency (milli-watt levels). The external electronics are housed within a stainless steel enclosure which is carried by the operator in a shoulder bag or belt pouch. The IMR electronics are connected to the loop antenna via a specialized multi-conductor serial/coaxial cable protected within a stainless steel braided harness. The electronics are powered by a small, internal battery pack. The IMR-PDA has a 3.3 AHr battery (5 VDC) and its own ruggedized cases for use underground.
The IMR, travel cases, and antenna are shown below (two IMR units per cases). In-mine receivers and dust-bag are packed into the IMR travel case for all transport. The only exposed socket or port is the receptacle for the loop antenna cable. The only user controls on this box are a single ON-OFF switch and indicator light. Note: The In-Mine RIM-6 Receiver system is currently non-permissible, though a permissible version is planned for late 2015. This approval will be for the receiver only (return entry).
The Graphical User Interface (GUI) software controlling the RIM-6 RX unit runs on its PDA computer. The application has seven main operating pages for command, control, diagnostics, noise analysis, data graphics, and multi-frequency operation. A collection of PDA screens are shown below.
Stolar has extensive experience over the last 30 years investigating the susceptibility of men, machinery, and explosive sources to its radiowave transmission devices. These studies include the susceptibility of various types of mining equipment to electromagnetic (EM) fields, their effects on blasting caps and remote detonation devices, the biological effects of EM waves from RIM equipment, and methane ignition susceptibility to radiating magnetic diploes. More detailed discussion of these issues can be provided upon specific request.