About: http://webisa.webdatacommons.org/353769936

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	To effect the lowering and raising of long strings of well pipe such as oil well casings, a spider is conventionally mounted over the rotary table on the working platform of an oil well drilling derrick.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com