Perhaps you should try some spelling variations:
"underground workings" » "underground openings", "underground wireless"
"underground banking" » "underground parking", "underground tanks", "underground openings"
"underground works" » "underground coal", "underground water", "underground gas"

Try widening your search to All Fields.

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("underground banking") OR ((("underground workings") OR ("underground works"))))) OR ("underground mining")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"underground banking\") or (((\"underground workings\") OR (\"underground works\"))))) or (\"underground mining\"))".
• Removing quotes may allow a broader search: (((( underground banking ) or ((( underground workings ) OR ( underground works ))))) or ( underground mining )).
• Adding a wildcard symbol may retrieve word variants: (((("underground banking") or ((("underground workings") OR ("underground works"))))) or ("underground mining"))*.