| 摘要 |
A process for the operation of a combined concrete and sand and gravel plant (1, Fig 1) comprises forming an initial 4 and an intermediate 5 settling pond by digging a hole in the ground and forming raised sides 21 by using the excavated material, forming a water outlet weir in each pond by an arrangement of spaced apart pipes 25 in the raised sides, connecting the ponds 4, 5 by an open-cut channel 14, providing a final settling pond (6, Fig 1) in connection with the intermediate pond via an open channel 15. During use the following steps are performed grading and washing sand and gravel, delivering the washed sand and gravel to a concrete plant for the manufacture of concrete, removing dirty water including sand fines left after the washing and grading process, delivering the dirty water sequentially to the settling ponds to allow sand and fines to settle out, recycling the cleaned water from the final pond to the sand and gravel plant, delivering cement to a weigher and sampling the concrete. |
