How did developments in science help the process of extraction of iron ore and/or provide alternatives to use of iron ore?
As with all techniques and processes, one must start somewhere. In the beginning, man was little better than the animals, working with his hands as a hunter gatherer. Somewhere along the line, someone figured out how to use stones as types of tools. A little more development, and we have the introduction of iron implements being used as weapons and tools. All these developments may be viewed as scientific developments, as they were separate stages of what was viewed as the "cutting edge of technology" at their time. Our ability to communicate became better, shared technologies and methodologies helped further the body of knowledge that began to accumulate at an exponential rate.
Iron ore and its uses have been contrasted as second perhaps only to petroleum as a natural resource. As is the case with all things, the future will only tell what iron will ultimately be replace with. When I was a teenager, the state of the art in sound systems was to have a modular amplifier with lots of wattage, really big speakers that could shake not only your house, but your neighbors house as well! The state of art in listening to music today is a device called an Ipod, which is connected to a small pair of ear phones that implant in one's ears. The time span we are talking about is about 20 to 30 years. It would not be unreasonable to expect something else to replace iron as the "new kid on the block" in terms of applicability and use.