The calculated distance (air line) between Mechelen-aan-de-Maas and Seraing is approximately 28 miles respectively 45 kilometers.
By car or train, the actual journey to Seraing is certainly longer, as only the direct route (as the crow flies) between Mechelen-aan-de-Maas and Seraing has been calculated here.
Air line (approximately)
45 kilometers
24 nautical miles