Well this isn't going to answer your question about exact speed but this ride was my very favorite as a child. I used to argue with my ds about using the "E" tickets for it. I could go on it over and over! It did not go fast it - it was a leisurely cruise through the wilderness
It was really slow - I don't know the speed, but it was like a nature tour with the narrator describing the scenes. I remember those mud pots - that was one of my faves, too, when I was a kid.