program there, and because of the paucity of published information con- 

 cerning the shelf in that area. 



Because of the line spacing involved in the CERC exploration program 

 at Miami, more closely spaced work might be required to more precisely 

 define the most suitable bottow areas prior to exploitation. Such a 

 program would be analogous to "development drilling" in the petroleum 

 industry, and to "blocking-out the ore" in the mining industry; conse- 

 quently, it is not a requirement unique to the offshore Sand Inventory 

 Program. Quantities of sand available are summarized in Table III. 



SECTION A 



The OSE Broward County report estimates a total sand volume of 66 

 million cubic yards within 1.2 miles offshore of Broward County. Of this 

 material, 36 million cubic yards is concentrated in the 60-foot platefiu, 

 within 1 mile of the beach. The remaining 30 million cubic yards lies 

 scattered in patches and thin blanket deposits in the 40-foot plateau and 

 on the inner flat. Over half of this material is concentrated in the 

 northern two-fifths of the segment where isolated sand pockets within 

 the 40-foot plateau begin to coalesce into larger bodies. 



From the south Broward County line to the Miami grid, a total of 66 

 million cubic yards of sand are estimated to occur. 



In the CERC Miami grid area, 14 statute miles south of the OSE Study, 

 there is a sand volume of 69 million cubic yards exclusive of the thin 

 and discontinuous patches generally occurring on the inner flat. Of this 

 amount, about 48 million yards are contained within the confines of the 

 40-foot flat 3 to 4 miles from the beach (Pigure 19). A smaller concen- 

 tration of about 5 million cubic yards lies on the offshore part of the 

 inner flat (Figure 19). Because of the nature of knoivn accumulations, 

 similar but smaller areas of recoverable sand can be forecast with reason- 

 able assurance to occur elsewhere on the flat. 



Approximately 16 million cubic yards of unconsolidated sediment occur 

 in the shoreface zone of Dade County. However, calculation of sediment 

 volumes in the shoreface is based on sparse data; no seismic lines were 

 run in this area due to the shallow water. Borings by the Corps of En- 

 gineers (Jacksonville District, 1961; 1968) indicated up to 18 feet of 

 sediment in the shoreface off Key Biscayne and less than 5 feet off 

 Virginia Key. 



SECTION B 



On the basis of the limited data available, morphology of the shelf 

 and subbottom, and geology of the region, the volume of material available 

 within the shelf area of Section B (north of 26''20' N) is estimated at 

 380 million cubic yards. The bulk of the sand is believed to have 

 characteristics similar to the fine gray sand recovered in the 10 cores 



38 



