The sequence in which hundreds of African natives attack the safari before being turned back by fire is taken from Stanley et Livingstone (1939). Note that star Jim Davis is costumed very much like Spencer Tracy was in that film. If you look closely, the rifles used in 1939 footage and this movie's spliced-in scenes are different models.
In the original uncut version the scene showing lava is in red tint. Most versions shown on television have this in black and white.
Even though the film was originally released in black and white with "red tinted" scenes near the end, The 1997 VHS release of the film has a scene shot in Technicolor. This was most likely done to replicate the original release with "red tint" scenes. The original tinted scenes were removed for television release. Early video releases continued without the tinted scenes. Until a 2023 DVD release that remastered the film to its original state with the tinted scenes back.
Use of a stopwatch might suggest that about 40% of this movie is stock footage.
The budget was one million dollars, rather big for a B picture.