The phrase "new reserves" means the recently discovered or additional supplies of something valuable, like oil, gas, or minerals, that were not known or accounted for before. Full definition
5 Oil companies seek the small fraction that remains, spending more than $ 150 billion a year hunting for new reserves. (discovermagazine.com)
And the third issue is that fossil fuel companies still invest, on the order of half a trillion dollars a year in developing new reserves. (climatechangenationalforum.org)
More likely is that for the foreseeable future we'll continue to find new reserves, and to develop new technologies for tapping into them. (judithcurry.com)