Carp Lake Mine LiDAR Survey

In October 2023, I was tasked with surveying an abandoned copper mine in Michigan's Upper Peninsula. The mine is located in the Porcupine Mountains Wilderness State Park near the town of Ontonagon. The purpose of the survey was to determine the total air volume in the mine.

914
Feet into the bluff
80.5
Million points captured
16
Scan stations
4
Survey crew members

The mine  is a former copper mine that was in operation from 1859 to 1929. The mine extends over 1000 feet into the bluff of the hill, and is estimated to have produced over 34,000 pounds of copper.

Bats reside in the cave, and are susceptible to white nose syndrome, a fungal disease that occurs in bats that reside in the cave. A group of biologists with the Department of Natural Resources suggested that by cooling the temperature of the mine, the presence of the fungus would be reduced.

A group of electrical engineering students at Michigan Tech were tasked with developing a cooling system for the mine. They needed a the total air volume within the mine to design the system. We, a group of geospatial engineering students, offered to scan the mine and provide the total air volume.

Survey

The survey was conducted using a Trimble X7 LiDAR scanner. The scanner was mounted on a tripod and positioned at various points throughout the mine. The scanner captured over 100 million points, which were then used to create a 3D model of the mine.

Me with a Windows tablet running Trimble Perspective, allowing us to preview our data and the registration confidence on-site. We donned PPE to avoid transmitting diseases we might have been carrying to the bats, and also to shield ourselves from the antibiotic-resistant gonorrhea the bats could harbor.
The scanner mounted on a tripod in the mine. Note the close quarters: the average height of the ceiling is about 7 feet.

Derivation

The process I used to derive the volume used a Blender plugin that determines the volume of any three-dimensional mesh. I used a simple shrink-wrap algorithm to convert the point cloud into a mesh. To estimate the uncertainty of the volume, I wrote a custom Python script that pertubated the mesh and calculated the volume of the new mesh based on expected observational errors from the scanner. After repeating this process 100 times, I was able to estimate the uncertainty of the volume to within about 6 cubic meters.

Results

The total air volume within the mine was calculated to be 1259 cubic meters, with an uncertainty of 6 cubic meters.

I published the point cloud data to Trimble Clarity , so the data is viewable in a modern web browser.

We also rendered a planimetric map of the mine, which is shown below.

A planimetric map of the mine.

Sensor data visualization

The electrical engineering team later reached out to me and inquired about building a custom tool to visualize temperature data from sensors within the mine. I built a mockup of a web tool  using Vite and React that would allow them to visualize the temperature data in real-time. You can also check out the source code  on GitHub.