Heavy earths

It is common experience that corrosive soils tend to be the heavy clays, especially if they have been subjected to working by, for example, heavy earth-moving machinery. Lighter soils are usually only corrosive if they have been contaminated by industrial debris, especially ashes, ferrogenous slags and carbonaceous material such as cinders. 

Name from barys (Greek = heavy) barite (or heavy earth) is the weightiest mineral (specific weight = A.5 g cm-3)... 

In 1783 he published an annotated translation of Torbem Bergman s Sciagraphia regni mineralis, and in the following year he communicated to the Philosophical Transactions his Experiments and observations on terra ponderosa (barium carbonate, or witherite) (96). He stated that the specimen he examined came from a lead mine at Alston Moor, on the Pennines of Cumberland. Although he at first mistook it for heavy spar (barite) he soon found it to be a compound of heavy earth (barium oxide) and fixed air (carbon dioxide) (97). 

Area samples may occasionally be deployed in locations requiring protection from weather and dirt contamination. In a recent study of heavy equipment operators exposure to diesel exhaust emission we had to support and protect instrumentation systems upon heavy earth moving equipment. Exposure to mechanical... 

Baryta Sulphate of Baryta 1 Heavy Earth Vitriol of Heavy earth Heavy spar... 

Light earths (La to Eu) Middle earths (Sm to Ho) Heavy earths (Gd to Lu)... 

The trends in the formation constants of the complexes reported here are much the same as reported previously for similar ligands. The over-all behavior of the chelates of N-benzyliminodiacetic acid and IV-methyliminodiacetic acid is virtually identical to that of iminodiacetic acid itself (13). The only major difference is attributed to the different basicities of the ligands which determines the absolute magnitude of the log Ki values but has little affect on the trends from one metal ion to another. For both ligands, the position of yttrium is in the heavy earths for both log Ki and log K2, although the actual value is slightly less than the normal value. 

The term sanitary landfill was first used in the 1930s to refer to the compacting of solid waste materials. Initially adopted by New York City and Fresno, California, the sanitary landfill used heavy earth-moving equipment to compress waste materials and then cover them with soil. The practice of covering solid waste was evident in Greek civilization over 2,000 years ago, but the Greeks did it without compacting. 

Element 39, with 4d 5s2 electron configuration, is also similar to the lanthanides. It occurs with the lanthanides in minerals the best source is xenotime, YPO4. Yttrium has properties approximately midway between those of Sc and La its compounds also resemble those of the heavy earths dysprosium and holmium, the ionic radius (0.90 A) being similar. 

Barytes, or heavy earth Clay, earth of alum Siliceous or vitrifiable earth... 

This is an example of how fluid power can be used to increase mechanical advantage. This mechanical advantage gained by fluid power explains how the heavy earth mover in Figure 11-12 is able to accomplish its job. 

The best known (sometimes infamous) method of surface mining is strip mining, in which strips of overburden are removed by draglines and other heavy earth-moving equipment to expose seams of coal, phosphate rock, or other materials. Heavy equipment is used to remove a strip of overburden, and the exposed mineral resource is removed and hauled away. Overburden from a parallel strip is then removed and placed over the previously mined strip, and the procedure is repeated numerous times. Older practices left the replaced overburden as relatively steep erosion-prone banks. On highly sloping terrain, overburden is removed on progres-... 

A method of surface mining in which strips of overburden are removed by draglines and other heavy earth-moving equipment to expose seams of coal, phosphate rock,... 

The REE are frequently subdivided into three groups (table 1) the light [lanthanum (La) to europium (Eu)], middle [samarium (Sm) to holmium (Ho)] and heavy earths [gadolinium (Gd) to lutetium (Lu)] (Topp 1965). 

Classification of the lanthanide elements into light, middle and heavy earths (after... 

One of the most striking effects of the lanthanide contraction is displayed in the behaviour of yttrium, which, although it has a much smaller nuclear charge (Z = 39), has a radius similar to holmium (Z = 67). For this reason yttrium is frequently isolated among the heavy earths and often included in discussions of the REE. 

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