scoria is a highly vesicular, dark colored volcanic rock that may or may not contain crystals phenocrysts .it is typically dark in color generally dark brown, black or purplish red , and basaltic or andesitic in composition. scoria is relatively low in density as a result of its numerous macroscopic ellipsoidal vesicles, but in contrast to pumice, all scoria has a specific gravity greater .
page 725 dragline at turkish coal association - yenikoy open pit coal mine, milas a dragline excavator is a piece of heavy equipment used in civil engineering and surface mining . draglines fall into two broad categories: those that are based on standard, lifting cranes, and the heavy units which have to be built on-site.
before the 20th century the heath was used to extract sand and gravel. victorian ordnance survey maps of the area show that there were lime kilns, marl pits and brick kilns, in addition to numerous extensive gravel pits, across the unenclosed part of the heath to the north-east of the city. the remains of the diggings can be found today.
the larvae of the antlions and the unrelated wormlions vermileonidae trap small insects such as ants by digging conical pits in loose sand, such that the slope of the walls is effectively at the critical angle of repose for the sand. they achieve this by flinging the loose sand out of the pit and permitting the sand to settle at its critical angle of repose as it falls back.
geotechnical investigations are performed by geotechnical engineers or engineering geologists to obtain information on the physical properties of soil earthworks and foundations for proposed structures and for repair of distress to earthworks and structures caused by subsurface conditions. this type of investigation is called a site investigation. additionally, geotechnical investigations are also used to measure the thermal resistivity of soils or backfill materials required for underground tra
the oil sands industry may build a series of up to thirty lakes by pumping water into old mine pits when they have finished excavation leaving toxic effluent at their bottoms and letting biological processes restore it to health. it is less expensive to fill abandoned open pit mines with water instead of dirt.
truck scales can be surface mounted with a ramp leading up a short distance and the weighing equipment underneath or they can be pit mounted with the weighing equipment and platform in a pit so that the weighing surface is level with the road. they are typically built from steel or concrete and by nature are extremely robust.
coarse soils – sand and gravel – can transmit wastewater away from the drain field before pathogens are destroyed. silt and clay effectively filter out pathogens but allow very limited wastewater flow rates. percolation tests measure the rate at which clean water disperses through a disposal trench into the soil.
early placer miners in california discovered that the more gravel they could process, the more gold they were likely to find. instead of working with pans, sluice boxes, long toms, and rockers, miners collaborated to find ways to process larger quantities of gravel more rapidly.