Exploring the next generation Omni Marker II family of electronic underground markers and their advantages in remote locations and industrial sites in a new white paper from Tempo at the National Resources Review.

The Omni Marker II family of underground markers delivers a reliable, cost-effective and convenient way for the mining industry to mark and locate buried utilities, allowing technicians and contractors to easily find the exact location of critical plant such as gas and power lines, water pipes, communications cables and more—thereby helping to avoid expensive damage and unfortunate accidents.

Enhance Safety and Reduce Costs by Permanently Marking Buried Plant
(Mark Govier - January 18 2021)

Abstract: We examine the benefits of using an electronic marker system to aid future location of valuable and dangerous buried services or other “underground treasure”. We summarise the advantages of knowing exactly where plant is installed and present a low-cost system to aid this process.



Many utility providers rely on burying their distribution network plant beneath the street and elsewhere for security, safety, and aesthetic reasons. However, that buried equipment does not have an infinite life and can be subject to stresses that can cause failure in the future; knowing exactly where that plant is buried can become a challenge later. Some types of buried plant are extremely difficult to locate precisely from above ground; most notably those which are electrically non-conductive, such as gas and water pipes and communication ducts carrying only optical fibres.

We will present a system that can be used to aid the marking, surveying, geotagging, and future precision location of buried plant. The system discussed is relatively low cost; proven to have a lifetime like that expected of buried plant and simple to use with little training.

What was needed was a complementary system for marking buried plant that was reliable, simple to use, both at the time of installation and when being traced and low cost. Thinking about variations upon theme of the “metal detector” mentioned above, the technology was expanded to a system where devices are buried that resonate at key electrical frequencies. By choosing a range of frequencies that are offset from each other sufficiently relatively standard electronic components can be used to create these resonant circuits leading to a relatively low-cost solution. They also contain no “active” electronics that may be more susceptible than simple “passive” components. To further protect these from environmental damage when installed they were enclosed in sealed plastic enclosures, made of the same long-life, impermeable HDPE as the ducts and pipes they are “protecting”.

The equipment used to locate these resonant markers resembles other locating devices but differs in the fact that it both transmits and receives. First a magnetic field is set up that is at a key marker frequency for a fraction of a second, this will cause any nearby marker that is tuned to that frequency to resonate in sympathy. When the transmitter is switched off, the buried marker continues to resonate for a fraction of a second, the decaying signal from this resonance can be detected and used to indicate presence of a marker of that key frequency on a display; often accompanied with an audible warning.


Buried Location Marker Signal Diagram


The Tempo EML-100 can sequentially scan all current industry standard frequencies so quickly whilst remaining sensitive, that it appears able to detect all types of industry standard marker concurrently.


Simplicity is Key
If any application is to be used successfully, all barriers to efficient use must be removed or made as small as possible. When installing the buried markers themselves there must be no complex requirements or installation instructions, the trench is a hostile environment, and no-one wants to be doing awkward work in such a confined space. Therefore, the ideal solution is a marker that can be installed in any orientation and simply tied to the buried service. With this basic requirement in mind Tempo created the Omni Marker™ II which contains a gimballed tuned coil assembly that always self-levels. When activated by a locator, this horizontal coil creates a near perfect vertical dipole response, meaning that installation orientation is not related to position accuracy or sensitivity. The peak of response is always directly above the marker. Tempo have recently complemented the Omni Marker II with Spike Marker that is a much more compact shape, like a pencil, that the user pushes into the soil alongside or above a service. These are ideal for use with shallower services or to be placed above services installed by HDD (horizontal directional drilling) as the drill is followed.

Continued in the white paper PDF here.

The Omni Marker II from Tempo Communications builds upon our three decades of experience with the original Omni Marker, providing the same reliability and range in a more compact package. With no active electronic components or potentially hazardous fluids, Omni Marker II is safe for the mining industry and can be located by all compatible marker locators. Dig Safe. Dig Right. Save Time.

How can we help you with your buried marker requirements?

Contact AusOptic directly by sending us a message or calling our office on 1800 677 623