Why is it expensive to extract copper from a contaminated land where the percentage of copper is low, using the traditional method?

The expenditure of the process is comparative to how much material (rock, dirt, whatever) you have to process. The more will be the  material to be route, the larger  will be the equipment, or the longer you have to run it, and the more power and other other materials you need. so that is why its expensive to extract copper from contaminated lan

hope it helps

hope it helps

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

thats a little if u want the answer just look it up on google thats what i do haha : )