Special Electric Mining Dredges - "Nu-Gulf I" & "Nu-Gulf II"
Owner: Mulberry Phosphates, Inc., USA
PROJECT INFORMATION:
In December 1981 Beker Phosphate Corporation of Bradenton, Florida, shipped the first phosphate rock produced by dredge mining. The use of dredges for both the stripping of overburden and the excavation of the ore body itself to the plant site was a first in the phosphate mining industry. In the past, dredges were used only for stripping the overburden or occasionally to excavate only the ore body itself.
Ellicott began the initial design work on August 1, 1980 and delivered the first dredge, "NU-GULF I" mechanically complete at the mine site May 8, 1981. Because of the short delivery schedule, Ellicott had to begin construction on the dredge hull and machinery while other items were still in the design stage. The contracts for electrical equipment and gear boxes were placed immediately followed by the design and construction of the hull and dredging ladder. Portions of the dredge hull had already been delivered to the mine site before the final designs of the spuds and spud frame were completed.
Both dredges feature submersible ladder pumps driven by electric motors mounted at the base of the ladder above water level. The dredges feature almost completely identical machinery so that spare parts inventories are kept to a minimum and maintenance is facilitated. The dredge hull of the larger overburden dredge was hinged in the middle to reduce bending stresses and permit less expensive construction.
Components available from standard Ellicott designs were used whenever possible thereby reducing design engineering costs. The dredge pumps, dredge controls, dredge lever room, cutter and most dredge castings were all standard Ellicott components.
As part of the contract, Ellicott was required to demonstrate that the dredge was capable of meeting strict minimum production standards. This demonstration was successfully concluded under operating conditions that proved to be considerably more severe than those called out in the contract. Pipeline length was approximately 30 percent longer than originally specified, and in some areas material hardness as measured by blowcount test turned out to be several times harder than anticipated. Ellicott quality frequently allows operators to meet output projections despite the unexpected.
SPECIAL FEATURES:
The overburden dredge ("NU-GULF I") was a specialized shore-powered electric dredge with extended hull length to provide a wide cut and highly efficient dredging operation. The matrix dredge ("NU-GULF II") was the first dredge ever used to mine phosphate ore featuring innovative deep-digging hinged hull design and long line pipeline capabilities unique to Ellicott.
The Matrix Dredge - "Nu-Gulf II"
The Overburden Dredge - "Nu-Gulf I"
The Overburden Dredge - "Nu-Gulf I"
Large project management in remote location, yet quick delivery achieved.
PRINCIPAL PARTICULARS: "NU-GULF I"
| Hull Size - length in feet |
215' |
| Maximum Digging Depth |
55' |
| Suction Pipe Size - ID |
20" |
| Discharge Pipe Size - ID |
20" |
| Dredge Pump Horsepower |
1500 |
| Excavator Horsepower |
400 |
| Total Installed Horsepower |
4500 |
PRINCIPAL PARTICULARS: "NU-GULF II"
| Hull Size - length in feet |
230' |
| Maximum Digging Depth |
92' |
| Suction Pipe Size - ID |
20" |
| Discharge Pipe Size - ID |
20" |
| Dredge Pump Horsepower |
2X1500 |
| Excavator Horsepower |
400 |
| Total Installed Horsepower |
4500 |
