According to the Company, it has been known for decades that Rare Earth mineralization occurs on other areas of its property in the form of various Rare Earth bearing carbonate and phosphate minerals, including both Bastnasite and Monazite.
Although the primary ore body that has been mined at Mountain Pass for the last 57 years contains economically recoverable heavy Rare Earth elements such as Dysprosium and Terbium, and the Company intends to produce certain heavy Rare Earth products (including Dysprosium and Terbium) from that deposit, it is primarily a Bastnasite deposit.
Discovered in 1949, bastnasite
was mined on a limited basis from 1952 to 1965.
TABLE 44 BAYAN OBO, INNER MONGOLIA, CHINA--TYPICAL BASTNASITE
ORE COMPOSITION (PERCENT OF TOTAL REO) 69
1953) The crystallography of bastnasite
, parisite, rontgenite and synchysite.
The ore minerals are bastnasite
, uranopyrochlore, sulphides, barite, and fluorite.
The sulfide-rich carbonatite orebody, which is quite interesting geologically, contains large quantities of massive bastnasite
and is considered to be the second largest rare-earth deposit in China.
Other associated minerals include calcite, dolomite, analcime, fluorite and weloganite, and very rarely also baddeleyite, dachiardite-Na, mordenite and bastnasite
but also relative exotica like gem zoisite, pargasite, ilmenite, bastnasite
Besides the predictably excellent bastnasite
crystals, there were lustrous black, platy ilmenite crystals to 6 cm; sharp, dark brown, incomplete tetrahedral crystals of genthelvite to 3 cm on edge; fine rutile as toenail-size, brilliant twins; and even a thumbnail crystal of the exceedingly rare baotite almost the equal, I'd say, of the one pictured in the article on Zagi Mountain.
Chalcopyrite, bismuthinite, bastnasite
and rarely linneite occur with the allanite-(Ce).
Zagi Mountain and related sites near Peshawar on the border between Pakistan and Afghanistan have recently begun to produce what are probably the finest specimens of bastnasite
, xenotime, and baotite known.
In recent decades, the Trimouns quarry has become well known as a source of outstanding crystals of several rare earth element-bearing minerals, including familiar species such as allanite, parisite and bastnasite
, as well as very rare ones such as hingganite, iimoriite and dissakisite.
crystal perched on an 8 X 10-cm feldspar matrix, showing some transparency.
de] booth, was a beautiful 5 x 20 mm xenotime crystal on a 7 x 10-cm matrix from the Zegi Mountain bastnasite
locality in Pakistan, marked 61,200.