How the Tasmanian dams case bound by the Koowarta case?

This is a question that needs to first asses the concept of precedent. Precedent is the concept that when a decision is made it forms judge made law by which the courts lower in the hierarchy must follow. However, because these two cases were heard in the same court of paramount importance ( the High Court) It was not bound to follow those precedents set earlier in the Koowarta case. This also allows for social change to be factored into decisions and allow the law to be as effective as possible.