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The IMDEX Solution for Accurate Core Orientation and Logging


By Marcelle P. Villegas


If you need to accomplish tasks such as ordering food, checking the movie schedules, or doing bank transactions, there are apps that one can download on a smartphone or tablet to do these and more. In mining, wouldn't it be great to have an app that can monitor real-time drilling activities and other stages and details of an operation? This is a fascinating option that is offered by a company called IMDEX.


Before the year ended last year, Mr Ryan Cairns of REFLEX (a branch of a company called IMDEX), was the Industry Hi-Lite Speaker at the Philippine Mining and Exploration Association (PMEA) Monthly Membership Meeting. The topic was "The Importance of Accurate Core Orientation and Logging - The Imdex Solution". [1] Mr Cairns is the Area Manager in Southeast Asia for REFLEX.


Ryans Cairns is a graduate of the University of Birmingham, United Kingdom, with a bachelor's degree in Geological and Earth Sciences/Geosciences with honours. He has work experience on exploration in the Philippines, Laos, Myanmar, India and Papua New Guinea.


Mr Cairns is an elected fellow of the Geological Society of London and an elected member of the Society of Petrophysicists and Well Log Analysts.


Real-Time Subsurface Solutions


In planning a mining operation, it is important to have accurate core orientation and structural logging. Thus REFLEX offers "Real-Time Subsurface Solutions." Mr Cairns explains, "The IMDEX group is made up of two components. The group where I work for is REFLEX and we specialise in geotechnical, geochemical and geophysical analysis."


"The other side of the business is AMC or Australian Mud Company Pty. Ltd. and they focus on the fluids used during the drilling process to keep borehole stable while still drilling."


AMC's headquarters is in Perth, Australia with offices in North and South America, Africa, and Europe.


"Together, AMC and REFLEX aim to redefine the way drilling fluids, equipment and technology are used to ensure execution of drilling programs are to specification -- on time, within budget and safety."


IMDEX group has five main solution sets, namely: Downhole Navigation, Structural Geology, In-Filed Geoanalysis, Driller Operable Geophysics, and Drilling Optimisation.


During his presentation, Mr Cairns focused on structural geology and the world of apps for mining activities. "We just released the world's first non-radioactive driller operated downhole gamma survey for geophysical analysis. We have Downhole Navigation which has devices that goes down drillholes in order to tell you the azimuth, dip and direction of that drillhole. And we have Drilling Optimisation, which is the drilling fluid, which is the AMC side of the business."


IMDEXHUB-IQTM


"If I want to order a pizza, I use an app. If I want to order a taxi, I use an app. However, in the mining and the exploration game, almost nothing is seen pushed to this level. We still have people writing information on pieces of paper, sending it downhill with a guy in a motorbike, to send it to a core shed to upload it to a database. This is the wrong way of doing things.


What we have really tried to push is to bring all of our instruments into real-time analysis," said Mr Cairns.


IMDEXHUB-IQTM (formerly called REFLEXHUB-IQTM) is an application that provides secure access to validated data which is transmitted from a range of sub-surface instrumentation, analytical instruments and mobile form data inputs. This provides a convenient and immediate access to the information you need, wherever you are. In effect, this will improve drilling contractor productivity and transparency across multiple streams of data. [2]


"So if I had a drilling project down in Zamboanga and I used one of the REFLEX instruments, whether it is geochemical or geophysical, that instrument would then send that data up to our cloud." He explains that in using this app, one can monitor the operation and check activity details while stuck in traffic on EDSA, for example. Moreover, using the IMDEXHUB-IQTM, he states, "I get a notification on my phone via this app and I would be able to see in real-time and start making real-time decisions on my exploration project."


Regarding structural maintenance, he said, “One of the most important questions that we get is 'Why do we need to have reliable and accurate structural measurements?’" It is important because it will help us predict the location where ore can be found or where more ore is located. "I need to be able to determine how my blocks of ore are going to behave during mining. Not only that, but I need to be able to predict the ground conditions, so when I am mining, I am mining safely and effectively."


Having the ability to predict the ground conditions will ensure safe mining and tunnelling.


Traditionally, anyone who has been a geologist in a core shed knows that collecting data is time consuming. It is a repetitive work where there is a tendency to end up with partial or inaccurate data which in turn may lead to fatal errors. [1]


Mr Cairns further explains the importance of accuracy of the drillhole surveys and the core orientation mark or line. "Quality Structural Measurements are always very important. They are only as good as the drillers and the geologist's care factor, and information they are trying to get from the drill hole. We need to have an accurate drillhole survey so these are the devices that go down the borehole path to tell us exactly where that core is coming from. If am a geologist or mining engineer and I am trying to make an analysis on a piece of core and I don't know exactly where that core is coming from in 3D space, then I am wasting my time."


"And the same thing comes from the orientation mark or line. If I don't know how that core looked prior to being drilled, I am going to make errors and make assumptions and going to be incorrect when I start my resource models or when I start to make my mine plans."


"So it is more than just taking a stand in measurement on a piece of core. We need to ensure that the survey, orientation and logging tools are fit for purpose." The next step is to have QA/QC systems in place. Then, he said that it is essential to provide proper training and supervision of the drillers and geologists. Lastly, he said, “I need to make sure that everyone takes ownership of this quality solution to highlight the importance of the

information that we are getting from this core."


"So why do we need structure and logging... and what does that play in terms of our 3D geology? Now, if I am drilling a piece of drill core and I don't have the exact angle, azimuth and depth of my geological context, I am going to open myself up to error margins when I start to make my resource models.”


As part of accurate measurement on the drill core, Mr Cairns also stressed on the need for a QA/QC. "Why is it important that we have QA/QC? These are some of the errors that unfortunately we don't want anyone to have, but they do have in the mining industry. For example, my orebody has moved 10m because I didn't accurately do surveys on my drill holes so I don't know where my core was coming from. I hit my drive, not my orebody. My pit ore has collapsed because my fault was meant to be 10 degrees deeper because I didn't accurately have core orientation marks to tell me what that degree was, or the ore wasn't meant to intercept and offset my orebody.”

The illustration above is a very basic design for some surface mining. The blue lines that are running down the edge are benches. “I have sunk the shaft and drilled some tunnels across. The red lines are drill holes running straight through. As you can see, it is planned straight. And the blue box is my orebody.


As you can see, my orebody is going down the center of my mine plan. I intersected underneath and we're all very happy,” he said.


"However, in the real world, not all drill holes are going to go straight. In fact, almost every drill hole is going to deviate to some extent. And if I don't have a proper understanding or control on that drill hole deviation, all the information that I am taking from my core, whether it is geological or structural, is opening myself up to errors. As you can see, the mine plan and the underground workings are completely off because we did not take the time during the drilling phase to accurately get that information.”

Pre-Requisites

- To accurately measure structures in drill core you need to know:

- where the hole has been drilled in 3D space and

- the orientation of the core in the hold

- Errors in the hole location and core orientation will significantly impact on the accuracy of your structural measurements.


DRILL HOLE SURVEYS

“A drillhole survey is a device that goes down the drillhole that is going to give me my azimuth or my direction and my inclination or my depth of the drill hole. so I am using this information to see exactly where that drill hole is going.”


Surveying the Hole


It is important to remember that all drillholes will deviate from their planned path. This deviation can be significant because it will affect the outcome of the next stages. Structural measurements might result in errors if the hole path is not accurately known. For that, survey tools are used. There are two kinds of survey tools, namely: magnetic and non-magnetic. The survey tool for non-magnetic environment is the Digital REFLEX EZ-TRAC. On the other hand, for the magnetic environment, the Gyroscope Survey Tools, and REFLEX Sprint-IQ Gyro are used.


Magnetic Survey Tools -- Digital REFLEX EZ-TRAC has features like having a built-in QA/QC functionality, auditable, digital data capture and transfer, data is easy to interpret, and it has robust, solid-state electronics. Using this tool, multiple survey shots can be taken at any time; however, it cannot provide an azimuth inside the drill rods or magnetic ground.


The Gyroscope Survey Tools is not affected by magnetic ground and drill rods, north-seeking gyro systems can automatically find true north, simplifying operation. It also has less downtime -- can be sued inside an overshot system, during the normal drilling cycle. It has easy to use software with built in QA/QC report generation.


REFLEX Sprint-IQ Gyro can be used at all hole inclinations from vertical to horizontal, and on multiple operation modes. It also functions on high-speed operation with more than 150m/minute continuous mode. This tool is twice as accurate compared to other Gyro tools.


CORE ORIENTATION


Core orientation is the process of determining the in situ orientation of the drill core in the ground. The drill core is marked to reference the gravimetric bottom or top of the core so we know what it looked like prior to being drilled. “If you don't know the orientation of your core then you can't determine the orientation of your structure. Errors in the position of the orientation mark will impact on the accuracy of your structural readings.” For correct Core Orientation, Reflex offers two main tool systems, namely: Contact or Front End tools and Non-Contact or Back End tools


Contact or Front End tools marks the core face at the top of the run. These include the Spears, Clay Shoes, REFLEX EZ-MARK, and REFLEX VERTI ORI.


On the other hand, Non-Contact or Back End tools orientates the core tube and marks the core face at the bottom of the run. This includes Electronic REFLEX ACT 3 & ACT-IQ, and Mechanical REFLEX EZ-ORI & Ball Mark.


More on the Non Contact Systems/Back End, they have REFLEX ACT 3/ACT-IQ as the electronic tool, and the REFLEX EZ-ORI and Ball Mark as the mechanical tools. The tools attach to the end of the core barrel and orientate the core tube. When the tube is retrieved it is rotated to its correct position and the orientation is marked on the core, which is locked in the lifter case. [1]


For more information:

IMDEX - https://www.imdexlimited.com/

REFLEX - https://reflexnow.com/

AMC - https://www.amcmud.com/


Reference:

[1] Cairns, Ryan (1 Oct. 2018). "The Importance of Accurate Core Orientation and Logging -- the IMDEX Solution". PMEA Monthly Membership Meeting Presentation, Oct. 2018.

[2] Retrieved from - https://reflexnow.com/imdexhub-iq/

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