The output is to-day relatively small in comparison with that of many other fields, but there are one or two permanent gold mines of great value working low-grade ore.
In small works the cupellation is finished in one furnace, and the resulting low-grade silver fined in a plumbago crucible, either by overheating in the presence of air, or by the addition of silver sulphate to the melted silver, when air or sulphur trioxide and oxygen oxidize the impurities.
In the case of the cheaper and more abundant minerals, such as coal and iron ore, and of large deposits of low-grade ores, the extent and character of the deposit can generally be determined by surface examinations at comparatively small expense.
The Alaska gold was derived almost wholly from the large low-grade quartz mines of Douglas Island prior to 1899, but in that year an important district was discovered at Cape Nome, on the north-western coast.
Large deposits of phosphate occur in Russia, and those in the neighbourhood of Kertch have attracted some attention; it is said that the Cretaceous rocks between the rivers Dniester and Volga contain very large supplies of phosphate, though probably of low grade.
Mexican coal is of a low grade - similar to that found in Texas, but as an official geological report of 1908 estimates the supply in sight at 300,000,000 tons its industrial value to the country cannot be considered inferior to that of the precious metals.
This is due to improvements in mining methods and reduction processes, which have made profitable low-grade ores that were not commercially available in 1880.
The cyanide process, introduced about 1890, is now one of the most important factors in the utilization of low-grade and refractory gold and silver ores.
Wet methods are only employed for low grade ores (under favourable circumstances ore containing from 4 to i% of copper has admitted of economic treatment), and for gold and silver bearing metallurgical products.
A large furnace and a Bessemer converter, the pair capable of making a million pounds of copper a month from a low-grade sulphuretted ore, will not occupy a space of more than 25 ft.
by ioo ft.; and whereas, in making metallic copper out of a low-grade sulphuretted ore, one day's labour used to be expended on every ton of ore treated, to-day one day's labour will carry at least four tons of ore through the different mechanical and metallurgical processes necessary to reduce them to metal.
Low-grade coal deposits occur in the east central part of the state and near the junction of the Gila and San Pedro rivers.
The .amount of ore taken for assay is generally one-half "A.T.," but in very low-grade ores one, two, and sometimes even four "A.T.s" are used.
The loss in quicksilver is small, as there is no chemical loss inherent in the process; the yield is relatively high, but the bullion is liable to be low-grade, on account of copper being precipitated and amalgamated.
Little attention is paid to the crop, the berries being frequently gathered from the ground, and consequently the coffee is of comparatively low grade.
In 1908 more than two-thirds of the total output was from the low-grade porphyry ores mined at Newhouse, Beaver county, and at Bingham, Salt Lake county.
In quality the coal varies from a low grade to a high grade bituminous, and some of the latter is good for coking.
People with mildly abnormal cells have ' low grade ' Barrett's.
At least 40 were shown during that period to have low grade dysplasia.
People with Barrett's esophagus may have low grade or high grade dysplasia.
No fever, or only low-grade fever may be present.
Back to top Study results A total of 18 patients with high-grade gliomas and eight with low-grade gliomas took part in the study.
AB - The role of postoperative radiotherapy in patients with low grade gliomas is not established yet.
I reckon I may even be able to lower this as I only used low grade thermal grease!
Eleven women had low-grade SIL while nine women had high-grade SIL.
Dump of iron-rich material - a small heap of low grade iron ores, including a few nodules of coal Measure ironstone.
T issue analysis by the pathologist divides precancerous changes into low grade or high grade squamous intraepithelial lesions (SIL ).
Despite a subsidy to the industry in the 1920s to develop processes to use low-grade German ore little was done.
low-grade gliomas took part in the study.
low-grade lymphomas as a group are often called indolent lymphomas because they tend to grow very slowly and need treatment less urgently.
low-grade ore, will last around 50 years.
low-grade fever may be present.
low-grade uranium in heavyweight sealed barrels at the Tuwaitha facilities.
Lymphadenectomy then revealed lymphadenopathy of low-grade non-Hodgkin's lymphoma.
Apoptosis is an important biological factor in low-grade lymphomas, and NO is able to prevent apoptosis.
At one time it was only the low-grade tabloid newspapers that encouraged popular superstitions like crystal-gazing or astrology.
Even without any increase in this consumption the present known reserves, of what is mainly low-grade ore, will last around 50 years.
Rub down the corners and edges of the plate with low grade sandpaper to avoid finger injuries!
None had stereopsis with TNO test and only three had low-grade stereopsis on the Titmus test.
The IAEA left 1.8 tons of low-grade uranium in heavyweight sealed barrels at the Tuwaitha facilities.
Subsequently low-grade quartz mines were found and developed, and have furnished a notable part of the gold supply of the country (about $100,000,000 from 1875 to 1901).
This segregation of the germ cells and their independence of the intestinal sac is an indication that the origin of these cells is not coelomic nor enteric, and until we possess further information as to the evolution of the complex genitalia of the higher Turbellaria we cannot hope to understand the presence of such highly modified structures in animals of an otherwise low grade or organization.
Rub down the corners and edges of the plate with low grade sandpaper to avoid finger injuries !
They are made with the same standards as other Blue foods and contain no fillers or low-grade meats.
The low-grade noise of the turning wind turbines and the shadows created by the rotation of the blades can potentially cause negative human health effects.
Another concern involves the low-grade noise pollution the action of the turning blades creates.
Most commonly, however, you'll find mid- to low-grade clear plastic, perhaps slightly tinted with a little bit of color, for anywhere between $10 and $40.
HSP is an acute but self-limited illness characterized by a low-grade fever (around 100.4°F[38°C]), purpura, joint pains (usually in the ankles and knees), abdominal pain, bleeding in the digestive tract, and inflammation of the kidneys.
Low-grade fevers often do not need to be treated in otherwise healthy children.
Children with viral croup usually have a low-grade temperature, but a few may have fevers up to 104°F (40°C).
Most of the remaining 40 percent experience mild, flu-like symptoms, low-grade fever, and fatigue that resolve without intervention in a few weeks.
Rarely, a low-grade bloodstream infection called chronic meningococcemia can occur.
A low-grade fever that lasts for several weeks is associated with autoimmune diseases such as lupus or with some cancers, particularly leukemia and lymphoma.
More than 85 percent of patients survive for more than five years after complete surgical removal of low-grade osteosarcomas (tumors that arise in mature tissue and contain a small number of cancerous cells).
Any low-grade fever or soreness can be treated with ibuprofen or acetaminophen as recommended by the pediatrician.
The third major symptom of juvenile dermatomyositis is a low-grade fever (one or two degrees Fahrenheit above normal).
The major symptoms of juvenile dermatomyositis include a characteristic reddish or purplish rash called a heliotrope rash; weakness or pain in the proximal muscles; and a low-grade fever.
Within about four to six days of acquiring the virus, an infected child may develop a relatively low-grade fever, ranging from 99 to 102°F (37.2-38.9°C).
In addition to the vomiting, the child may have a headache, low-grade fever, dizziness, pain in the abdomen, heavy drooling, and diarrhea.
The child may also experience a low-grade fever, fatigue, and nausea.
Usual symptoms include nasal congestion, coughing, sneezing, throat irritation, and a low-grade fever.
Symptoms of low-grade fever, irritability, and soreness at the injection site following the MMR immunization can be relieved with an analgesic such as acetaminophen as recommended by the pediatrician.
Among the most common physical reasons for excessive crying are earaches, viral illnesses, and other causes of low-grade fever.
Some patients with polyarticular JA will have other symptoms of a systemic illness, including anemia (low red blood cell count), decreased growth rate, low appetite, low-grade fever, and a slight rash.
Early symptoms may also include a sore throat, low-grade fever, headaches, loss of appetite, nausea and vomiting, and diarrhea.
Cigarette smoking raises the white blood cells count, activating the immune system; however, smoking causes low-grade chronic bronchitis, low birth weight infants, and weakened natural immunity in newborns.
However, a low-grade fever or cold is not a contraindication for routine vaccinations.
Large stones with low prices may be inferior, low-grade diamonds with numerous flaws, a lack of sparkle, or other devaluing characteristics.
Some people would even say that a good quality cubic zirconia has more fire and sparkle than a low grade diamond that may be cloudy and dull.
The choice is likely to stretch from low grade golds through to the finest platinum.
If the stone is set in stainless steel, silver, or low grade gold, it is more likely to be a lesser quality or fake gem.
It is important to note that lower grade metals are harder than high grade gold or platinum and as such if a low grade metal is worn against a high grade metal, the high grade metal may wear away.
This shifts the curve of the lower back, which may cause a low-grade but nagging back pain to develop, for example.
The word usage examples above have been gathered from various sources to reflect current and historial usage. They do not represent the opinions of YourDictionary.com.