LiDAR is a remote sensing technology that penetrates through vegetation and water, producing detailed 3D images of the Earth’s surface both above and below water. Examination of the black and white LiDARÂ image below (Figure 1), which shows Nonza Beach and the sea bottom immediately to the west of the beach, indicates a markedly different submarine topography in front of the beach.
LiDAR image of the land and sea bottom topography at Nonza Beach, N. Corsica. The blue line indicates sea level. (Image credit: Aurania Resources Ltd.)
You can see the submarine areas to the north and south have an irregular topography due to the rocky seabed. The sea bottom west of the beach is mostly smooth; the hollows have been filled in with sand. As demonstrated by historical air photos (Figure 2), it is believed that the waste from the historic Canari Mine, which had filled in the port of Nonza, also filled in and covered the sea bottom at Albo and Nonza Beaches.
Figure1. Historical air photo on the left and present-day photo on the right, showing the development and progradation of the Albo and Nonza Beaches over time. The beach material is believed to be composed of waste from the historic Canari Mine and also extends up to 600 m west of the shoreline below water. (Image credit: Aurania Resources Ltd.)
One day was spent in reconnaissance sampling of the sea bottom to test this hypothesis (Figure 4). A high-field strength Sm-Nd magnet was used on the end of the fishing line, and an innovative reel to retrieve it was put together from a power drill by Stefan. A total of four samples were collected in front of Albo Beach and six samples in front of Nonza Beach.
Figure 4. Two rare earth magnet sea probes, both covered in magnetic black sand. (Image credit: Aurania Resources Ltd.)
In each case, the magnet collected large amounts of magnetic sand off the sea bottom. Samples of this sand have been sent to ALS Chemex in Seville, Spain, for analysis. Since nickel is not present in the magnetite, any nickel in the assays would indicate the presence of awaruite.
The Company has been in touch with WOKO Magnet- und Anlagenbau GmbH of Duisburg, Germany, who manufacture a marine electromagnet that possibly could be used to recover the magnetic sand. This magnet (Figure 5) is used to clean up ordnance from WWII in the sea and to remove metal trash.
Figure 5: WOKO Magnet- und Anlagenbau GmbH, marine electromagnetic in operation. (Image credit: Aurania Resources Ltd.)
Aurania believes the recovery of sand by this method would have minimal disturbance to the environment. The sand is obviously already at the surface and is probably a bottom lag, winnowed by the currents so that the heavy metal grains are preferentially concentrated.