I just happened to be searching for one of these this morning and discovered 18 of them had become available free online just yesterday.
Vol. I. Tungsten and Manganese Ores.
http://www.archive.org/details/specialreportson01geol Vol. II. Barytes and Witherite.
http://www.archive.org/details/specialreportson02geol Vol. III. Gypsum and Anhydrite.
Vol. IV. Fluorspar.
http://www.archive.org/details/specialreportson04geol Vol. V. Potash-Felspar, Phosphate of Lime, Alum Shales, Plumbago- or Graphite, Molybdenite, Chromite, Talc AND Steatite (Soapstone, Soap-Rock and Potstone),Diatomite.
http://www.archive.org/details/specialreportson05geol Vol. VI. Refractory Materials : Canister and Silica Rock, Sand for Open-Hearth Steel Furnaces, Dolomite.
http://www.archive.org/details/specialreportson06geol Vol. VII. Mineral Oil, Kimmeridge Oil Shale, Lignites, Jets, Cannel Coals,
Natural Gas. England and Wales.
Vol. VIII. Iron Ores : Hematites of West Cumberland, Lancashire and the Lake District.
Vol. IX. Iron Ores (contd.). Sundry Unbedded Ores of Durham, East Cumberland, North Wales, Derbyshire, The Isle of Man, Bristol District and Somerset, Devon and Cornwall.
http://www.archive.org/details/specialreportson09geol Vol. X. Iron Ores (contd.). The Hematites of the Forest of Dean and South Wales.
Vol. XI Iron Ores (contd.). The Iron Ores of Scotland.
http://www.archive.org/details/specialreportson11geol Vol. XII. Iron Ores (contd.). Bedded Ores of the Lias, Oolites and Later Formations in England.
http://archive.org/details/specialreportson12geol Vol. XIII. Iron Ores (contd.). Pre-Carboniferous and Carboniferous Bedded Ores of England and Wales.
http://www.archive.org/details/specialreportson13geol Vol. XIV. Refractory Materials : Fireclays. Resources AND Geology.
http://archive.org/details/specialreportson14geol Vol. XV. Arsenic and Antimony Ores.
Vol. XVI. Refractory Materials : Ganister and Silica-Rock, Sand for Open-Hearth Steel Furnaces, Dolomite.Petrography and Chemistry.
http://www.archive.org/details/specialreportson16geol Vol. XVII. The Lead, Zinc, Copper and Nickel Ores of Scotland.
http://archive.org/details/specialreportson17geol Vol. XVIII. Rock-Salt and Brine.
Vol. XIX. Lead and Zinc Ores in the Carboniferous Rocks of North Wales.
http://www.archive.org/details/specialreportson19geol Vol. XX. Lead and Zinc : The Mining District of North Cardiganshire and West Montgomeryshire.
http://www.archive.org/details/specialreportson20geol Vol. XXI. Lead, Silver-Lead and Zinc Ores of Cornwall,Devon and Somerset.
http://www.archive.org/details/specialreportson21geol Vol. XXII. Lead and Zinc Ores of the Lake District.
http://www.archive.org/details/specialreportson22geol Vol. XXIII. Lead and Zinc Ores in the Pre-Carboniferous Rocks of West Shropshire and North Wales.
http://www.archive.org/details/specialreportson23geol Vol. XXIV. Cannel Coals, Lignite and Mineral Oil in Scotland.
http://www.archive.org/details/specialreportson24geol Vol. XXV. Lead and Zinc Ores of Northumberland and Alston Moor.
http://www.archive.org/details/specialreportson25geol Vol. XXVI. Lead and Zinc Ores of Durham, Yorkshire AND Derbyshire, with Notes on the Isle of Man.
http://www.archive.org/details/specialreportson26geol Vol. XXVII. Copper Ores of Cornwall and Devon.
http://www.archive.org/details/specialreportson27geol Iron Ores of Great Britain (4 Volumes)
http://archive.org/details/cu31924004694257