Mining Drone Orthomosaic (left) and DSM (right.) of a section of the leach pad. DSM is overlaid with 5m contour lines.

A QuestUAV Case Study from Kazakhstan


INTRODUCTION

Mine operators know that safety precautions are of utmost importance in the daily routine at a mining site. Conventional surveying methods involved considerable effort and resources on the ground.

Starting with electronic tachometers and later with ground GPS, surveyors have had to enter high-risk areas on the ground and spend considerable time to finish a survey. Some of the most acidic areas cannot even be entered as the risk to health and safety is too high. When compared with conventional ground surveying, it has been proven that the use of drones or Unmanned Aerial Vehicles (UAVs) for surveying immensely reduces the exposure to risk for surface workers involved on site.

 

Aerial Survey with QuestUAV 200 Surveyor drone (left) vs. ground survey with a total station (right).

Instead of walking a mining site with ground equipment, areas of whatever risks involved are surveyed by flying over the site. UAV surveys can be done in a fraction of the time of a ground survey and generally provide higher accuracies. Surveying projects that usually take weeks with conventional surveying methods can now be completed in just a few hours. Hence, UAV technology minimizes risks while reducing costs and boosting productivity.


TEAM QUEST IN KAZAKHSTAN


This autumn TEAMQuest was called by KAZ Minerals to help raise safety and efficiency to a higher level than ever before at one of the biggest open-pit mines in eastern Kazakhstan. Two local teams (8 people) went through an extensive two weeks training program on professional flight operations and aerial open-pit surveying with a QuestUAV 200 Surveyor. Following training by QuestUAV, both teams now fly the two Q-200 Surveyors on a daily basis with the following objectives:

View of the mining site (leach pad)

 

  • To monitor mine status
  • To monitor & plan pit and leach pad progress
  • To map & plan infrastructure (roads, buildings)
  • To monitor the perimeter security fence
  • To estimate stock pile volumes
  • To monitor & plan site rehabilitation
KAZ Minerals is focused on copper mining, producing both copper cathode from oxide ore and copper in concentrate. The pit development started in early 2013 supported by extensive surveys on the ground. It is predicted that the mine will become the biggest mining operation in Kazakhstan within the next three years. A crucial part of KAZ Minerals strategy for a safe and efficient pit development is to replace conventional survey methods with latest UAV technology. KAZ Minerals decided to go with QuestUAV as we provide a robust and stable system for difficult environments, high quality sensors and ongoing support for the flight operations.

 


EQUIPMENT AND DATA ACQUISITION


Since September 2016 KAZ Minerals have surveyed their mining sites and expansion areas on a daily basis with two QuestUAV 200 Surveyors. The QuestUAV Surveyor carries a Sony A6000 camera with a 16mm wide-angle lens providing image data down to 2.9cm GSD at 400ft. The images are the basis for 3D models, topographic site maps, infrastructure maps, pit volume estimations as well as maps for security and surveillance. Geospatial accuracy (cm-level) is achieved by combining image data with a combination of permanent and temporal Ground Control Points (GCPs) distributed over the mining site.
Bungee launch of the QuestUAV 200 Surveyor
Generally, the Q-200 Surveyor has been designed to complete high-quality aerial surveys in the quickest way possible in any environments ranging from desert and tropic to glacial and Arctic/Antarctic. The automatic camera trigger and the gimballed camera system allow to take pin sharp pictures even at high wind speeds of up to 55 km/h.

The Q-200 Surveyor is launched with a bungee launch line and is either landed via parachute or belly landing. The latest version of the Q-200 Surveyor comes with a Post-Processing-Kinematic (PPK) option, which provides high mapping accuracies down to 3cm without the need of physical ground control points.

 


APPLICATIONS


Daily flight missions have become an essential part of the KAZ Minerals site planning and mine development. The work of the flight team forms the basis for all further work in developing the mineral resources - distributing information to engineers, planners and geologists. Aerial measurements are used to develop and display the plans, maps and profiles required for mining and exploration. Three of the major applications are explained in the following sections.

 


MINE STATUS


The basic application of the survey results is to provide a general overview of the status of the mine. Orthomosaic, Digital Surface Model (DSM) and 3D point clouds are used to keep the KAZ Minerals management up to date about recent developments in the open-pit and the leach pad. The figure below shows sections of the orthomosaic illustrating the level of detail gained from QuestUAV data.

 

Sections of the orthomosaic of the open pit.

SITE DEVELOPEMENT


Orthomosaic and DSM are the basis for an in-depth topographic analysis of the development of the mining site. Valuable information can be extracted from orthomosaic and DSM, such as infrastructure maps (roads, buildings), water bodies, contour lines, the flow of water, risk maps etc. These datasets in combination with expert knowledge of mining personnel are used for the development of intelligent management plans for the development of the mine.

 

Orthomosaic (left) and DSM (right.) of a section of the leach pad. DSM is overlaid with 5m contour lines.

VOLUME ESTIMATIONS


UAV based measurements are the fastest and easiest way to measure stockpile volumes. Photogrammetric software, such as Pix4Dmapper or Agisoft Photoscan allows to automatically calculate volumes on the basis of aerial imagery. KAZ Minerals has proven that UAV based measurements are not only faster, geodetic accuracies are even higher when measurements are taken from a UAV.

 

3D Model of a stock pile (left) and pile definition for volume calculation (right);red:volume;green:base area.
volume calculations
Volume calculations are performed on the basis of the Digital Surface Model (DSM). The difference between the base elevation of a pile (green) and the pile elevation (red) is the Cut Volume – when the terrain is higher than the base. Fill volume is the volume between the base and the terrain when the terrain is lower than the base. The Total Volume is the sum of Cut Volume and Fill Volume.

 


CLIENT ASSESSMENT


KAZ Minerals stated that the QuestUAV system greatly improved the surveying work at the mining site in terms of:

  • Improved worker safety
  • Higher efficiency
  • Increased site development productivity
  • Higher accuracies of the geodetic work

Nowadays UAV surveys are the basis for all further work related to developing the KAZ Minerals mining site, including engineers, planners and geologists.


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