Masonry Magazine October 1979 Page. 18
TRI-DELTA BLOCK PLANT
Now for a pictorial tour of the plant. The pictures correspond numerically with the various areas depicted in the flow chart on the preceding pages.
Photo No. 1-Aggregate loading area with the cement silo in background next to the plant structure. See details 1, 2 and 3 on flow chart.
One of the first tasks facing the Tri-Delta plant management was the efficient handling and supply of aggregate and portland cement. Unique are the four storage bins which supply the two types of lightweight granite aggregate, coarse and fine, called Riolite. To create this storage system, the desert surface was excavated 26 feet and the final structure was elevated 11 feet above ground.
This allows delivery of the aggregate to be easily discharged from the two hopper trailers so that they can make their round trips to the pits, which are located some 25 miles up in the Nevada mountains, numerous times a day.
Total capacity of the bins is 450 tons, with the coarse aggregate ranging from "to 4"; the fine material ranges from a #4 to a pan size.
The batching of the granite aggregate is automatic, with conveyors transporting the material to the material hoist. Each of the four collector conveyors are controlled by timers; once the hoist is fully charged it moves upward towards the mixer. This mix is then automatically dumped into the mixer with the aggregate being pre-wet by adding approximately 95 percent of the water to the mix.
Cement is stored in a silo adjacent to the manufacturing plant and is transported to a cement scale by a screw conveyor which feeds the mix directly into the mixer. At this point, the remainder of the required water is added to the mix. (See photo No. 1.)
The mixer is a MASA Record HM 2000, which has a capacity of 2.625 yards. The material is mixed by three revolving and mixing stars. Each of the three stars has four stirring arms with wear-resistant shoes. Mixing time for each batch is three minutes. With this extremely fast cycle the mixer offers a number of advantages:
►Its heavy steel construction, which adds greater durability to the unit.
►Cleaning of the unit is expedited because of the accessibility of the moving parts.
►Cement loss is almost eliminated since the cement is added directly to the mix.
►Last but not least is the added safety factor. Once
Photo No. 2-The material hoist about to discharge its load into the mixer. See details 4 and 5 on flow chart.
Photo No. 3-The MASA block machine. See detail 6 on flow chart.