Marine Phosphorite Deposit Delineation Techniques Tested on the Coronado Bank, Southern California
Authors: Barne Burton B. 
Published: October 2008

A typical marine phosphate deposit previously known to exist on the Coronado Bank Southern California was used by the Bureau of Mines Marine Minerals Technology Center as an ocean laboratory for testing equipment and techniques associated with the Center's deposit delineation research program. Several close grid pattern surveys were completed in May and June, 1968. A model was developed which identifies the deposit characteristics and represents the product of data correlation and interpretation. New information is revealed concerning the localization of higher grade phosphorite deposits on the Bank.

A unique correlation, based on physical evidence gathered in the process of testing delineation techniques, is described thatlinks the seafloor lithology and regional tectonic activity of the late. Tertiary to environmental conditions and organic activity of the seafloor. These key factors control the formation, concentration and surface distribution of phosphorite. Statistics, contoured maps and photos are provided in detail to substantiate an interpretation which resulted in the identification of five (S) zones of high phosphate (PZOS) content. Thirty-one (31) core drill sites have been selected for further delineation by core drilling.

FOREWORD

In January 1968, Research Director Arthur P. Nelson of the Bureau of Mines, Marine Minerals Technology Center established a new approach to coordination and management for marine field operations. A team concept was implemented to meet the need for strengthening coordination during the planning and preparation phases for offshore field campaigns, and to centralize direction during the actual field operation phase.

The author was appointed as Team Manager to effect such a program for the California Marine Phosphorite Project. Team members were assigned to the project from each of the following MMTC component activities:Deposit Character Identification Research.Deposit Delineation Systems.Ship's Operations.Mining ResearchMetallurgy Research

Associate members were also appointed to the team. This complement included personnel from the Administrative Branch of the Center and other Government agencies as well as participant from industry who were working cooperatively with the Bureau of Mines General Orientation Program contract.

The phosphorite project provided a direct involvement of industrial cooperators in the Center's Southern California Offshore Campaign. This complied with the primary goal of the Center to encourage and assist the development of a United States industry-owned-and-operated marine mining industry.

The report covers the results of only two parts of a three-part comprehensive delineation program planned for the Coronado Bank. A number of reasons precluded completing the Phase III-core drilling program. At this time, the program effort to accomplish the drilling has been indefinitely postponed for lack of funds, but hopefully will be activated before fiscal year 1972. Sediment cores would have provided direct evidence of the third dimension and thus provided a measurement of the vertical distribution of the phosphorite on the bank as well as evaluation of systems and techniques for sampling deep water sediments.