WorldWide Drilling Resource

Frequently-Used Geological Terms Part 59 Glossary Adapted from the Dictionary of Geological Terms O Opencut Mining - A form of surface mining in which the valuable rock is exposed by removing the overburden. Coal, numerous nonmetals, and metalliferous ores (such as iron and copper) are mined in this fashion. Open Form - A crystal form whose faces don’t enclose space such as a trigonal prism. Open Hole - An uncased well or borehole, or the portion extending below the depth in which casing has been set. Also refers to a borehole free of obstructing objects and materials. Optical Calcite - Crystalline calcite so clear it can be used for optical use. Order of Crystallization - The apparent chronological sequence in which crystallization of the various minerals of an assem- blage takes place. Ordovician - Named after a Celtic tribe, the Ordovices, this refers to the second earliest period of the Paleozoic era (after the Cambrian and before the Silurian), and is believed to cover the span of time between 500-440 million years ago. Ore - The naturally occurring material from which a mineral or minerals of economic value can be extracted at a reasonable profit. Orebody - A continuous, well-defined mass of material containing enough ore to make extraction economically feasible. Ore Control - Any tectonic, lithologic, or geochemical feature considered to have influenced the formation and localization of ore. Ore Magma - A magma which may crystallize into an ore; the sulfide, oxide, or other metallic facies of a solidified magma. Ore Mineral - The part of an ore, usually metallic, which is economically desirable. Look for more terms next month! WWDR photo of opencut mining opera- tions at the Kennecot Copper mine in Utah. Open the Doorway to all the Event Photos during the 2017 Empire State Water Well Drillers Association Annual Meeting. To see all the pictures from this event, go to: www.worldwidedrillingresource.info/gallery/2017/ESWWDA2017, or just click here. Feel free to download at will and print the photo(s) of your choice. Compliments of WorldWide Drilling Resource ® . Photos are copyrighted and released for personal use only - no commercial use permitted. 40 MARCH 2017 WorldWide Drilling Resource ®