Near the entrance you'll find a gate crystal. Also Tetran will come here with his shop (the same you saved on the Leviathan).
You won't find anything worth of interest in here - all you have to do is to run to the end of the village and talk to it's leader. She tell you that Mjirn (you were looking for her) isn't in the village. You have to find her and bring her back. Exit the jungle using the same way you did while coming here.
In front of the jungle's entrance you'll find two imperial soldiers. Talk with one of them [screen 1] - he'll ask you for a potion for his heavily injured friend. Give him one potion and he'll lend you his chocobo out of gratitude. Use this opportunity and go to Ozmone plains. Just upon entering the next area search chocobo trails on the ground on the left side [screen 2]. When you find them follow them and you'll get to the entrance of Henne Mines.
Later on return to the place where you have helped the soldier. You'll find a small, glittering object.
It will be the gratitude for you help - two Alarm Clocks.
Approach the human bodies before the entrance to the mains and then go inside.