When nurse Dorfman opens the trap door to the mine to see Jim lying injured, there is a shovel to the right of a pit prop. After she climbs down and reaches Jim, the shovel is to the left of the prop.
When Sanders, with doctor and sergeant, visit the village a side shot shows them passing the first hut. Their shadows are clearly seen on the ground, yet in the following approach shot the shadows are considerably lengthened and reach halfway up the side of the hut.
In the final scene Todd and the girl, in a boat on the river, look up and see an aircraft supposedly taking the other girl back to civilization. This Lufthansa Boeing 707/700 is clearly trimmed for landing with wheels and flaps extended. Any 707 of that era powered by the Pratt and Whitney JT3D engine would be emitting vast amounts of smoke when on full power after take off as to gain max power. In tropical conditions it used water injection to increase thrust, creating a massive amount of soot.
The film made in 1963 is contemporary but the hospital up river from the capital has no telephone or even a radio .