The phrase "vast quantities" means a large amount or abundance of something. It can refer to an extensive quantity, great numbers, or copious amounts. The word "vast" emphasizes the magnitude and size of the quantity in question.
This rising heat and the moisture form a powerful weather system, a natural pump that pulls up water and moves it in vast quantities hundreds of miles to the mainland. (scientificamerican.com)
Unless perhaps you're a new mother who wants to produce vast quantities of milk, or is having trouble with lactation. (supernaturalacnetreatment.com)
Housing, highways, rail lines, construction of all kinds, consumed vast quantities of stone, gravel, and crushed rock. (slaw.ca)