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DRONE VS TERRESTRIAL SURVEY METHODSVALE MOATIZE COAL PROJECT

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Agen

da

1. INTRODUCTION

2. TYPICAL DRONE WORKFLOW

3. ADVANTAGES OF DRONE SURVEY

4. TYPICAL DRONE DELIVERABLES

5. DRONES CAN ALSO BE USED FOR

6. MOATIZE PROJECT DATA COMPARISON

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INTRODUCTION

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This presentation will highlight some of the advantages when we want to compare typical Drone

survey vs old terrestrial survey methods using a combination of GPS, Total Station & Laser

Scanner. We will also have a look at the different deliverables that can be produced when using

Drone data and also the typical workflow that will be followed to produce Drone data.

Firstly, using a Drone can vastly reduce the time spent collecting accurate data. By acquiring

raster data from the sky – in the form of geo-referenced digital aerial images, with resolutions as

sharp as 1.5 cm (0.6 in) per pixel – you can gather millions of data points in one short flight

With collection made so simple, you can focus your energy on using and analysing data, rather

than working out how to gather it.

With such a large increase in the amount of physical data being collected, this does mean an

increase in office time spent processing and utilising this data. However this expansion is

cancelled out many times over by the huge time savings a drone produces out in the field. Large

jobs that once took weeks can now be completed in just a few days, and that a week’s worth of

traditional data collection is now achieved in just one day.

Last but not least, less time spent on the ground means staff safety is improved by minimising risk

to surveying teams when measuring sites such as mines, unstable slopes and transport routes.

Simply choose take-off and landing locations that are out of harm’s way.

INTRODUCTION

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TYPICAL DRONE

WORKFLOW

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Flight Planning Setting Out GCP Flight

Importing Images

Creating DEM and 3D Point Cloud

Analysis / Creating

Deliverables

Final Reports and Deliverables

TYPICAL DRONE WORKFLOW

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ADVANTAGES OF DRONE

SURVEY

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ADVANTAGES OF DRONE SURVEY

• Efficiency – Drone surveys makes the collection of data easier

and faster compared to terrestrial survey methods

• Accuracy – By acquiring raster data from the sky with resolution

as sharp as 1.5cm per pixel millions of points can be gathered in

a short flight, Currently we achieve more than 100+ points per m²

• Safety – Hard to reach and hazardous areas can now be

surveyed without risk of injury

• Affordability – Previous methods of aerial surveying carried high

costs, UAV survey enables cost effective solutions for anyone

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TYPICAL DRONE

DELIVERABLES

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TYPICAL DRONE DELIVERABLES

We will touch on some of the most common deliverables that are being used

in the industry today.

• 3D Referenced Dense Point Clouds

Densified point clouds can be produced in all common file formats; .LAS , XYZ or any

form of ASCII file. This drone survey of Moatize TSF produced a densified point cloud

of 193 522 614 points and was surveyed and processed within 4 hours.

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• High Detailed 3D Surfaces

High detailed accurate surfaces are produced from dense cloud data. True slope

profiles are surveyed and accurate Toe & Crest positions can be produced. Even on

inaccessible areas accurate surveys can be obtained without any risk. This drone

survey of Moatize Sect 2 pit a surface was produced with 9 694 406 faces and a total

of 4 858 752 vertices. The survey and data was produced within 2 hours.

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• Georeferenced Orthomosaics

A georeferenced aerial image is produced with resolutions of up to 2cm/pix.

Georeferenced orthophotos can be produced in either .TIF, .ECW or .DXF format and

can be very useful in reporting and monitoring of specific areas.

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• DEM – Digital Elevation Model

Digital elevation models can be created from acquired dense point cloud and

produced in either .TIF, .BIL or .XYZ

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DRONES CAN ALSO BE

USED FOR

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DRONES CAN BE USED FOR

Drones are not only limited to obtain survey and mapping data but can also be useful

for other applications

• Mining equipment count

• Surveillance and security

• Disaster management

• Engineering and construction inspections

• Environmental inspections

• Drainage contours

• Surface stability monitoring

• General area inspections

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MOATIZE PROJECT

COMPARISONS

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We will have a look at the comparison between the quality of data and also the

turnaround times for deliverables that was collected by using old survey methods and

by means of drone survey. The biggest improvement was definitely the stockyard and

ROM areas, as Incredible Technologies cut the turnaround time for those surveys by

more than 80%.

Just a look at some of the turnaround times for areas surveyed by both methods:

It is definitely evident that tasks that proved challenging to complete can be done

seamlessly and efficiently with drone technology.

MOATIZE PROJECT TURNAROUND TIME COMPARISON

AREA SURVEYED OLD METHOD DRONE

TSF Area Not Surveyed 1 Hour

Stockyard Survey 3 Days 30 Mins

ROM Surveys 2 Days 1 Hour

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Some of these more challenging areas that was surveyed:

Trying to survey these areas using old survey methods would take months and some of them would be impossible to complete.

Since Incredible Technologies started their drone operations they have covered a total of 36 463 hectares to date adding up to over 75 000 individual photo stations.

AREA SURVEYED AREA (ha) TIME

TSF Area 460ha 1 Hour

Section 4 Waste Dumps 745ha 2 Hours

Section 2 Waste Dumps 705ha 2 Hours

Sect 1 Phase 1 Area 1360ha 4 Hours

Sect 2A New Waste Area 402ha 1 Hour

Sect 4 - HDV Haul Road 406ha 1 Hour

Sect 2 Thermal & Rejects Area 218ha 45 Mins

Sect 2 Spillway Area 705ha 2 Hours

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STOCKYARD SURVEY COMPARISON

As seen above a typical screenshot of a stockyard survey conducted using both laser

scanner and gps survey method.

The above mentioned task the scanner had to be moved a total of 89 times to achieve

an overall survey. And took a total of 3 days to complete.

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Because of restrictions on scanning angles and distances there are quite a lot of lost

data sections or dead spots(shadows) as seen in above screenshots.

This means that there is not always a very accurate representation of the surveyed

stockpiles as some of the data is lost and the vertices for the surfaces are created

only from the data that is available.

Lost data

sections

Bad vertices

Lost stockpile

crests

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Above image illustrates the same survey process done by means of drone survey.

The entire stockyard was surveyed in 30 minutes and data was delivered within an

hour of completing the survey task.

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Because images are captured from above there is always accurate representations of

stockpile profiles and because of quality of point density accurate vertices and faces

are created

No lost data

Good

vertices

Accurate

stockpile crests

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SECT 4 IN PIT BANANEIRA COMPARISON

Above images compares the differences of an in pit bananeira rom survey in Moatize

Section 4 using laser scanner and drone.

A volume calculation was conducted using the same baseline survey for both survey

methods and produced a difference of 1 500 m³ in volume.

Because of insufficient survey point data from the laser scanner caused by shadows it

is creating inaccurate vertices and that causes difference in volumes.

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SECT 2 HIGHWALL FAILURE MONITORING

The drone was used to survey and inspect the failing highwall in Section 2A.

As seen above using normal survey methods to achieve this results would be nearly

impossible to achieve, as there are many dangerous and hard to reach areas.

However with the drone it was completed within less than 2 hours.

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MOATIZE TAILINGS STORAGE FACILIY SURVEY

As seen above a complete and total survey was conducted using drone survey

method and the survey was completed in 1hour and total area covered was 460ha.

Using normal survey methods this task would take weeks, and surveying all areas

would prove difficult especially tailings settling areas that are wet.

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MOATIZE SECTION 1 & 6 PHASE 1 SURVEY

A drone survey was conducted for the Section 1 & 6 area and the survey was

completed in 4 hours and total area covered was 1 360ha.

The drone proved to be very efficient conducting this survey as using normal survey

methods would have been an extremely difficult task due to the size of the area and

very vegetated areas.

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WASTE DUMP UPDATES SECT 2 & SECT 4

The drone was also used to update all the waste dumps in Sect 2 and Sect 4.

Complete surveys were produced easy and efficiently.

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MOATIZE HDV HAULROAD TO SECT 4

As seen above, a drone survey was done on the HDV Haul Road to Sect 4.

The entire survey and deliverables were produced in 2 hours.

Surveying this area using normal survey methods would have taken days to complete

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MOATIZE SECT 4 PIT UPDATE

A survey update of the entire Sect 4 pit was done.

The survey was completed in 1 hour and the total area covered was 310ha.

Surveying this area using laser scanner would have taken days to complete.

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MOATIZE SECT 4 NORTH WALL INSPECTION

As seen above a survey was done of Sect 4 North Wall Area close to the community.

The survey was completed in 1 hour and the total area covered was 310ha.

The survey proved very useful to inspect and evaluate the encroaching houses at the

boundary fence.

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The Drone proved a very useful survey method for the expanding operations here at Vale Moatize.

With the data collection made so simple, more energy can be used on analysing data, rather than

working out how to gather it.

Using the drone for data collection reduces the need for workers to enter potentially hazardous

areas. The small, portable size of drones make them ideal for collecting data in a variety of

different environments like roadways and steep terrain.

Because operations are ramping up and everything is becoming bigger and better, the drone will

definitely be on the forefront of delivering accurate, visual data that will make decision making,

planning and reporting easier and efficient.

CONCLUSION

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Contatos

• Shepherd Ngwenya – shepherd.ngwenya@vale.com - tel. +258 823065164

• Leon Potgieter – leon@inctech.co.za - tel. +27 827865703

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