WA is undeniably the resource centre of Australia, contributing about 58pc of Australia’s mineral and energy exports.

But with 92pc of its 2.6m inhabitants living in the southwest corner, the rest of WA is a variation of the “Wild West” –– sparsely populated towns with poor infrastructure, rugged terrain and a landscape of reds, greens, coppers and browns that stretch into the horizon.

In other words, when someone pictures the Australian outback, they’re picturing WA.

That same rustic beauty and isolation, though, can make surveying a challenge.

And it makes surveying for mining a real test of adaptability and logistics skills.

It can take about 1.5 days to get to the first site, and once there, there is total isolation, with no resources and climate conditions that can range from 0 to 50oC.

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The sparse, rugged road systems make navigating anywhere a long journey.

And if the weather turns bad on the job and the surveyor didn’t plan well, he could be completely stranded.

On top of the inherent unpredictability of the outback, there are technological challenges that increase its complexity: limited cell phone coverage, inconsistent RTK cellular or radio communication, and geodetic control points that are hard access.

But now, advances in precise point positioning (PPP) technology have helped to resolve these obstacles and enable surveyors to optimise their real-time productivity without compromising accuracy.

Next generation Global Navigation Satellite System enhancement has helped tame the wilds of WA, enabling operators to increase data collection efficiencies, reduce costs and boost bottom lines.

Leading the way has been Trimble, which, backed by a legacy of GNSS technology leadership and surveying expertise, provides surveyors and Geographic Information Systems professionals with reliable, innovative survey solutions that meet their distinct requirements.

Taking a typical RTK reading.

The case for active mining

A big supporter is Phil Richards, a professional surveyor and associate director of Perth-based RM Surveys, who has focused much of his work in WA on supporting active mining companies.

For example, for the past 15 years, one iron ore producer has contracted him to travel more than 600km from Perth to measure exploratory drill hole collars.

These remnants of drilling activity are 3mm-thick segments of PVC, about 150mm in diameter, which protrude about 300mm out of the ground at typically a 60o angle.

Measuring the center of that above-surface collar is critical in the exploration process to enable the company to develop a geological model of its mineral resource underground.

Managing ten prospect sites across 300km, the number of drill holes could vary from year to year, but often they would have up to 100 holes spread out over a few prospects at a time.

Since 2007, Mr Richards has been using Trimble R8 GNSS receivers, and, more recently, Trimble R10 and Real Time Kinematic (RTK) technology to acquire the drill collar measurements.

On average, each prospect is 5km by 2km and has its own coordinate network. Depending on the number of collars and distance to each, Mr Richards would set up an array of RTK base stations (between two and nine) on known control points to set project control.

Using his GNSS receiver, he’d either drive or walk to each drill collar, set the foot of the range pole on the center of the collar at ground level, take a reading and record the measurement in Trimble Access field software on a Trimble TSC3 controller.

Although the need for multiple base stations added hours to the projects, the RTK method consistently provided the needed accuracy.

Walking between two collars to save 0.5 hours of driving.

X marks the spot

In 2015, the iron ore company restructured its mineral exploration program.

Rather than drill large numbers of exploratory holes across a few prospects, the new focus was to drill fewer holes spread over the entire project area, but that was going to be problematic for Mr Richards’ traditional RTK routine.

Previously, when it was predominantly surveying and less traveling, the RTK approach worked well for the project, even though setting up base stations is time consuming,” Mr Richards said.

But when that switched to less surveying and more traveling, continuing with RTK was going to increase costs because each time I have to set up my base station, that’s an extra hour.

If I have 10 drill-collar zones, that’s 10 hours. And if my base station is 10 minutes away, it adds more time and expense if I have a problem with it or I can’t get a reliable signal, and I have to travel back to it to fix it.

The reduced number of collars and the increased distances between them required a more efficient method to make the project profitable.”

Mr Richards’ dream solution would enable him to use a single GNSS receiver system, much like working within the VRS networks available in the more populated areas of Australia.

The approach would give him mobility and flexibility and consistent real-time GNSS measurements.

He began testing other modern solutions, including Trimble’s CenterPoint RTX correction service, which is built on a network of GNSS tracking stations around the world that stream multi-frequency, multi-constellation data to the company’s network control centers.

Advanced data processing algorithms analyse the three main error sources: satellite orbits, clock offsets and atmospheric effects and develop models and correction data.

This information is delivered to GNSS rovers via L-band satellite communications, which combine the correction data with thrie own satellite observations to produce accurate positions.

Mr Richards ran five trials in conjunction with varied exploration surveys to test the reliability, efficiency and accuracy of the RTX approach as a viable alternative to RTK.

Choosing different test sites across 1000 km of terrain, he took RTX measurements of survey control points with his R10 and compared them to the same positions acquired with RTK.

The technology consistently delivered on performance,” Mr Richards said.

Most importantly, this technique enabled me to work without a base station and obtain real-time GNSS positions with centimeter accuracy anywhere––even in isolated WA.”

Based on the trial results, Mr Richarda adopted the CenterPoint RTX technology to integrate into his survey workflows.

Into the outback

Getting the R10 ready for use.

The R10 and CenterPoint RTX technology have been Mr Richards’ core technology for each campaign since the drilling project.

With CenterPoint RTX, I can get right to work as soon as I reach my first drill collar site,” Mr Richards said.

I don’t need to spend time with a base station so I’m much more mobile and that alone can save me a whole day’s work.

I’m not limited by distance or the base station’s signal. It’s a brilliant tool and it’s a game changer for remote surveying.”

A couple of years ago, Mr Richards was contracted to survey 40 drill collar holes spread around all 10 of the client’s prospects.

His team mounted the R10 GNSS receiver on their vehicle and set out for the first site at sunrise one morning.

About 30 minutes from arriving on site, they activated the CenterPoint RTX and monitored the initialisation via Bluetooth from inside the cab.

With the RTX solution initialised and ready to go, Mr Richards carefully dismounted the R10 and set the range pole onto a control point he previously established to calibrate site control.

He navigated to the first stake indicating a collar, verified the collar number given, set the R10 on the center of the collar and via the TSC3’s software he entered the collar number and recorded the RTX 3D position.

He then moved on to the next stake and followed the same routine, repeating it 39 times over 2.5 days.

With the distances involved and the large area we’re working in, the RTX really comes into its own for this project,” Mr Richards said.

If I had had to use an RTK approach, and set up multiple base stations 10 different times, it would’ve added at least another day to the job.

If you take all the driving out of it, we reduced 10 hours work of actual surveying time to one hour. That savings not only pays for my yearly CenterPoint RTX subscription, it’s a smart way to increase your profit line.”

The data was processed in the office in Perth, measurements were verified, and input into a spreadsheet for the client.

For last year’s campaign, Mr Richards and a colleague were contracted to acquire accurate 3D positions for 13 drill collar holes stretched across two major prospects that are about 150 km apart, about 700 km northeast of Perth.

Using the small WA town of Cue as a base, they drove to the first prospect about 60 km away, using the travel time to initialise the CenterPoint RTX positioning solution.

Within the 15km-wide area, they had to acquire measurements for eight drill collar holes.

They calibrated the R10 receiver to the nearest control point to tie into the site’s coordinate system and moved through the area, methodically recording positions of each collar hole.

Despite the relatively few collars to measure, it took them about five hours to collect the data because the rough terrain made the site difficult to navigate.

Still in daylight, they drove to the next prospect, which contained five holes at significant distances apart.

By the time they reached the site, they could only complete one hole, so they camped out on site and measured the remaining four holes the next day.

All told, they finished both prospect sites in 1.5 days –– a project that would have taken 2.5 days had they used RTK.

Given the project format, with so much travel time and less surveying time, RTX is really the only way to do it,” Mr Richards said.

There’s little surveyors like Mr Richards can do to reduce travel times in the remote areas of WA, but venturing into the wild with a reliable and cost-efficient tool that can produce real-time, centimetre-accurate positions in seconds is a reassuring advantage for staying competitive.

 

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