Structure from motion could be done with ground based photos, especially if the camera was on a tall pole. Multiple photos would be needed which included each part of the surface from many different angles. So you would need permission to walk the pole around the entire area of interest. If the camera had GPS, the resulting 3D model could be scaled (if certain sfm programs were used).
Depending on the size of the quarry relative to the size of the private property, aerial photos (kite, balloon, drone) could be taken from the periphery. You would have to encircle the quarry, and if you can't get close enough the 3D model would be of poor resolution.
Even if you had access to the quarry, and the surface is mostly sand, the photos will not have distinct textures and might not stitch together very well. So sfm on sand quarries, sand piles, and coal ash piles is a challenge unless you can put distinctive markings on the homogeneous surfaces.
But it appears that this sand quarry has filled with water and photos would not reveal the excavation. So in this case photographic volume calculations might be impossible. Depth finder transects from a canoe might work.
To monitor the sand being removed over time, a camera station could be established where the trucks exit the private property. Motion detection could trigger the camera when a vehicle passed. That way the number and type of truckloads removed from the site could be determined.