Vast discoveries of phosphate off North Carolina's scenic coast could help the United States maintain its leading, independent role in world agriculture. Furthermore research is needed to determine if the phosphate beds can be mined profitably. But, says geologist Stanley R. Riggs, at least one bed is "as rich as anything they're mining on land."
Some US experts see a phosphate shortage developing. They project a switch from the US being an exporter of phosphates -- a key ingredient in fertilizers -- to an importer within 25 years.
This would make US food production somewhat dependent on a foreign source. The No. 1 exporter of phosphate today is the Arab nation of Morocco.
But other American experts say there is enough phosphate in the US to be mined profitably while meeting the nation's needs, and even be exported, for 1, 000 years.
Whichever estimate is correct -- and Congress would like to know -- the new phosphate discoveries could substantially extend the known minable US reserves.
By most estimates it would be at least 10 years before the offshore phosphate beds could be mined.
Isolated discoveries of phosphate have been made off North Carolina's coast since at least the mid-1960s. But the new discoveries show phosphate deposits exist in a much broader area than previously detected.
With National science Foundation funding, geologist verified phosphate deposits in and area running about 30 miles parallel to the coast (near Wilmington, N.C.) and from near shore to about 100 miles out. The deposits are beneath 50 to 130 feet of water.
Core samples and seismic soundings were used to verify the deposits.
Mr. Riggs, a professor at East Carolina University in Greenville, N.C., was involved in the effort that led to the new discoveries. He says that, based on the similarity in geological formation and on isolated sampling and studies by other, "there is at least as much and possibly even more" phosphate offshore from North Carolina to south Florida than onshore in these states.
Florida produces more than 80 percent of the nation's phosphate, and North Carolina is also a major producer.
Officials at Ocean Minerals Company of Mountain View, Calif., are studying the new offshore findings. Conrad Welling, senior vice-president of Ocean Minerals (a partnership of Standard Oil of Indiana, Royal Dutch/Shell, and Lockheed Corporation), says equipment for such mining does not exist but his firm could develop it.
Mining phosphate in about 50 feet of water would cost about $10 a ton above today's onshore costs, says consultant Michael Zellars. The mining can be done by dredging, he says, with existing technology. His Lakeland, Fla., consulting firm conducted a study of such mining for the federal government.
Increasingly tight environmental regulations on Florida phosphate mining add to its cost, says an aide to Florida Gov. Bob Graham. Vast tracts are despoiled , and reclamation is extremely costly -- if feasible at all.
Such problems make ocean phosphate mining attractive, argues Riggs. But, according to some sources in the US Geological Survey, the federal government has shown little interest in promoting offshore mining.
But, says one Geological Survey official, the new phosphate discoveries may "trigger" greater federal interest.
Dr. Richard Sheldon, senior researcher for the Survey, estimates there's enough on-land phosphate economically extractable at today's mining pace to last "a thousand years." But the General Accounting Office, using federal Bureau of Mines data based on mining company plans, says the US will be forced to import phosphates by the early 21st century.