10.3　Selection of Borrow and Quarry Areas

10.3　Selection of Borrow and Quarry Areas

10.3.1　The sources of natural building materials shall include materials excavated at building site，soil，natural sand and gravels and materials exploited from borrow areas.The material sources shall be selected according to the construction requirements for the building materials′quantities，quality and supply intensity.After analyzing material source distribution，reserves，quality，exploitation and transportation conditions，and working out an excavation-fill balancing plan，the selection of shall be finalized through techno-economic comparison on the basis of geological explorations and experiments under the principle of best quality and cost effectiveness.

10.3.2　The borrow areas for an earth-rock fill dam shall be selected in compliance with the following principles:

1　The physical-mechanical characteristics of the dam materials conform to the quality standards of materials for dam use.

2　The reserves are relatively concentrated，the top soil is thin while the material layer is thick，and the total reserves can meet the requirement for dam filling use.

3　The borrow areas shall be used as required for different parts of the dam body.

4　A part of the borrow areas in nearby locations is reserved for flood retention of dam.

5　The borrow areas are easily exploited with broad working area and short，transportation distance，and there is a disposal site nearby.(https://www.daowen.com)

6　Little or no occupation of farmland and forests.

10.3.3　The selection of borrow areas for concrete aggregates shall be in compliance with the following principles:

1　If there are abundant reserves of natural sand and gravels at areas adjacent to the project and their quality meets the standards，they shall be selected as the major material source.

2　If the reserve and quality of natural sand and gravels from the borrow areas adjacent to the main works cannot meet the requirements，artificial aggregate should be excavated and manufactured nearby.Priority should be given to excavated materials if they are of large quantities and good quality and can meet the requirements of construction progress.

3　Little or no occupation of farmland and forests.

10.3.4　For the selected borrow areas，the exploitation planning，slope protection，soil and water conservation and environmental protection measures shall be proposed.