First: Plans are plans, so long as they give dimensions in feet, and inches, they can be used in any scale.(they do require a scale ruler).
That said, generally a mining plant will be of a size, and style, determined by the material being mined, and whether or not it is processed on site. Plans for a "plant" will usually have to be modified to fit the scale real estate, selective compression will usually have to be practiced to get a building that fits the space you have.
If you are scratch building, you can use a photo, and adjust the number and size of windows and doors, and the overall size of the finished structure. A kit, may also have to be "adjusted" to fit.
http://forum.zealot.com/attachments/4651d1046032920-gsstn1.jpg shows a gas station, plastic kit, that originally had two service bays. One was removed so the building would fit in the allotted space.