Energy in South Australia and trap in the deeper heat. Due to the low permeability of granite, the hot rocks must undergo hydraulic fracturing and be stimulated to allow a flow of water through the system to produce energy. This heat is slowly conducted to shallower rocks near the surface. Petratherm propose developing the geothermal energy in the more permeable sedimentary rocks that overlay the hot granite, a process called Heat Exchange Within Insulator (HEWI). While somewhat cooler, in many cases they do not require hydraulic fracturing. It is estimated that one percent of geothermal energy shallower than five kilometres below the earth's surface
More Hot Rocks (Big Hits & Fazed Cookies) it was recalled and something a little more practical was compiled (ABKCO would revisit this concept with 1975's "Metamorphosis"). The result was "More Hot Rocks (Big Hits & Fazed Cookies)". Featuring the hits that could not be shoehorned onto its predecessor, as well as first-time release of many previously UK-only releases, the double album was quickly pressed and distributed into North American shops in December 1972, reaching No. 9 in the US and going gold. Like "Hot Rocks 1964–1971", "More Hot Rocks (Big Hits & Fazed Cookies)" would not see an official UK release until 21 May 1990. Allmusic's Richie