He started up an illegal mining operation near the mountain, where he and his men believe that there is gold for them to dig. As they do so, they use the water from the river to irrigate their operation, where they separate the dirt from ore with chemicals, which are then later spilled out into the rest of the river heading towards the jungle. Because of this, it has caused a plague among the animals drinking it (even Tantor almost fell victim to it). Even the Waziri tribe fell victim to the plague, as they used the river for their crops and traveling. Needless to say, McTeague doesn't care about the toxicity of the chemicals and continues dumping them into the river, as he still wants to be rich. Upon learning about the mine, Tarzan and his friends ally with the Waziri tribe to build a dam to block the river and then break it down to have the speeding water destroy the whole mine for good, leaving the river fresh and clean again. McTeague and his men then leave in a huff, but not after McTeague angrily swears revenge against Tarzan and the Waziri tribe for ruining his mining operation. However, he presumably does not keep his promise after being scared off by Tarzan and Basuli roaring like leopards at him, as he is never seen again.