Cyanide leach technology and its applicability to Alaskan conditions

Cover of: Cyanide leach technology and its applicability to Alaskan conditions |

Published by U.S. Dept. of the Interior, Bureau of Mines in [Anchorage, Alaska] .

Written in English

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  • Leaching -- Costs.,
  • Cyanide process.,
  • Chemical engineering -- Alaska.,
  • Chemical engineering -- Nevada.

Edition Notes

Book details

Statementby Denise A. Herzog.
Series[OFR -- 39-90], Open file report (United States. Bureau of Mines) -- 90-39.
ContributionsUnited States. Bureau of Mines.
The Physical Object
Paginationii, 31 p.
Number of Pages31
ID Numbers
Open LibraryOL17751645M

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The U.S. Bureau of Mines conducted a study of cyanide leach technology used in Alaska's mineral industry from through Literature and cost data were obtained for mines in the contiguous United States, Canada, and Alaska that use cyanide to recover gold and silver.

Get this from a library. Cyanide leach technology and its applicability to Alaskan conditions. [Denise A Herzog; United States. Bureau of Mines.].

Judging from the ore being treated, carry out bottle roll or leach test on the leach feed, optimizing the cyanide concentration (dropping it from ) using the plant's residence time or varying that and measuring each CN concentration used, pH used against the level of recovery and residual cyanide, that should give a good head start although.

Treatment of Cyanide Heap Leaches and Tailings applicable to leach heaps, pads, and cyanide-bearing tailings impoundments and ponds, but did not apply to vat leach facilities using cyanide. Since the original August cyanide policy and bonding modification, BLM has issued two additional changes to its cyanide policy.

prior to reclamation. Cyanide treatment technologies are discussed in detail in Section 3. Closure and reclamation are discussed in detail in Section 4. State regulations and their applicability to closure and reclamation is discussed in Section 5.

Tank Operations (Carbon-in-Pulp and Carbon-in-Leach). conducted consisted of four leach tests carried out with varying reagent addition rates. Test PC1 Aiming to determine leach recovery with no accelerant addition, Air only leaching.

Estimated concentrate grade of % Au, solids mass ~24 kg, producing leach conditions as follows: Solution volume litres Cyanide addition 5 kg. Herzorg, A. D., " Cyanide leach Technology and Its Applicability to Alaskan Conditions, " Open File Report, U.

Department of the In-terior, Bureau of Mines, 89 (). The Bureau of Mines investigated the applicability of carbon-in-pulp process for recovering silver from low-grade ores. The reasons for the research were to illustrate a practical procedure for the process design of carbon-in-pulp adsorption circuits using leach slurries and simple equipment, and to illustrate how equations of adsorption theory relating to rate data and equilibrium adsorption.

Thiosulfate is also an alternative lixiviant to cyanide for leaching gold under low acidic or low basic conditions (pH ), while cyanide is more suitable under basic conditions for pH > 10 [ The predominance of the Cu(CN)2– complex under cyanide deficient conditions is yet another reason to maintain excess free cyanide in the leach.

By avoiding copper in solution, gold is more effectively loaded on the carbon rather than being displaced by copper. Moreover, excess copper in. Many precious metal ores contain copper minerals in various amounts. These copper minerals dissolve in cyanide solutions to a greater or lesser degree depending on the particular copper mineral or minerals present, their fineness, and the dissolving effect of the cyanide solutions.

In the process of dissolution the copper combines with, or as it is termed, consumes cyanide and, if the amount.

The successful application of heap leaching to the extraction of gold from low-grade deposits has been one of the main factors in higher output since the s, especially in the United States. It is a low cost process that extracts a soluble precious metal or copper compound by. The heap leach and milling processes, which involve dewatering of gold-bearing ores, spraying of dilute cyanide solutions on extremely large heaps of ores containing low concentrations of gold, or the milling of ores with the use of cyanide and subsequent recovery of the gold-cyanide complex, have created a number of serious environmental Cited by: for cyanide control at Ergo has been one of leach/cost optimization.

However, more recently, with the increased public awareness of cyanide in the environment, a secondary but increasingly important motivation for control has been to ensure that only the minimum amount of cyanide is added to the process whilst not compromising leach Size: KB.

Gold Mining with Cyanide REPORT ON I Repeal of the Ban on Cyanide Heap Leaching in Gold Mining WHAT IS CYANIDE AND WHAT DOES IT DO IN THE ENVIRONMENT Cyanide is a general term, referring to various specific cyanide compounds.

Cyanide (CN) itself is a simple, organic anion (negatively charged ion) consisting of carbon and Size: 58KB. justify cyanide use in mining on those operating these mining facilities.

Internationally, several counties, like the Czech Republic, Greece, Turkey, Germany, Hungary, Costa Rica, Argentina, Ecuador, and some states of the United States (e.g. Montana) have banned cyanide leach technology in gold and silver mining.4 In Korea, the cyanide leaching.

years after the mine began operating, the leach pad began leaking cyanide into surface and groundwater. Discharges from the heap leach pad violated cyanide standards in the neighboring stream for 3 months in6 months inand at least 4 months in File Size: 1MB. Cyanide leach vats at Alaska's Fort Knox Mine View of the cyanide leach vats in use at Alaska's Fort Knox Mine.

operations batch cyanide leach this concentrate with or without additional reagents. The method of agitation and solution recovery vary. The most common method of agitation is by a high-speed propeller mixer and the least expensive but time-consuming method of solution recovery is by decantation after settling and by repeated decant Size: KB.

The practise of cyanide leach mining has been prolific around the world since the ’s. It makes the mining of extremely low grade ores profitable while creating huge quantities of waste. But cyanide is highly toxic, and in recent years the dangers of using the chemical has become evident in a string of cyanide related mining accidents that.

Cyanide Leaching Of Gold, Laboratory Bottle Tests. Using a ml graduated cylinder, measure out ml of the solution for use with the leach test. Now, with the ml cyanide solution and the g of ore in the bottle, place the lid on firmly, making a seal. Due to its instability, Caro’s acid is produced on-site and used immediately for cyanide detoxification with only minimal or no storage.

The reaction of Caro’s acid with cyanide (and WAD cyanides) does not require a catalyst such as copper as the reaction is rapid and typically complete within a few minutes. H 2 SO 5 + CN → OCN + H 2 SO 4Cited by: 7. In Australia and North America, a mining technology called cyanide heap leaching is used by mining companies to level en-tire mountains of rock containing only small concentrations of gold.

To extract the gold, miners spray a solution of highly toxic cyanide salts (which react with File Size: 4MB. Hydrogen cyanide is a colourless liquid with an odour characteristic of bitter almonds and a vapour pressure of kPa at °C; Footnote 2 it is completely miscible in water.

Footnote 3 Potassium cyanide, a white granular powder, and sodium cyanide, a white crystalline solid, are both readily soluble in water.

Footnote 2, Footnote 3. The term cyanide generally refers to one of three classifications of cyanide, and it is critical to define the class of cyanide that is to be treated. The three classes of cyanide are: (1) total cyanide, (2) WAD cyanide, and (3) free cyanide, as shown in Figure Each of these forms of cyanide has specific analytical methodologies for its measurement, and it is important that the.

Cyanide is present at manufactured-gas plant (MGP) sites in oxide-box residuals, which were often managed on-site as fill during active operations. Cyanide can leach from these materials, causing groundwater contamination. Speciation, fate, and transport of cyanide in a sand-gravel aquifer.

Cyanide is used to leach gold from the ore. Which of these potential scenarios associated with cyanide leach ponds would cause the greatest immediate impact to far reaching areas. Spill directly into a stream. Which of these hazardous chemicals is polluting waterways in Central and South America due to small-scale gold mining practices.

concentrations, cyanide becomes toxic to soil microorganisms, and passes through soil into underground water. Cyanide concentrations of 1 microgram (one-millionth of a gram) per liter of water can be fatal to fish 6. Free cyanide volatilises at temperatures slightly File Size: 1MB.

The draft initiative, filed first with the Legislative Services Division on its long path toward being placed on the November ballot, would restore the legality of cyanide leach mining. It would also require that leach pads, ponds and other mine elements containing cyanide to keep all the cyanide-tainted liquids from leaking, including the.

Cyanide toxicity and their environmental impact are well known. Nevertheless, they are still used in the mining, galvanic and chemical industries. As a result of industrial activities, cyanides are released in various forms to all elements of the environment.

In a natural environment, cyanide exists as cyanogenic glycosides in plants seeds. Too much consumption can cause unpleasant side by: The effects of cyanide on neural and synaptic function in hippocampal slices.

Neurotoxicology *Aitken D, West D, Smith F, et al. Cyanide toxicity following nitroprusside-induced hypotension. Can Anaesth Soc J *Akcil A, Mudder T. Microbial destruction of cyanide wastes in gold mining: Process review. Non-cyanide lixiviants of current interest.

A recent review by Ritchie et al. () highlighted the importance of a comparative study, using cyanide as the bench mark, of the characteristics of alternative leaching systems.

Chloride, thiosulphate, sulphide, ammonia, and sulfite have been identified as the low cost systems; the first two are Cited by: GUIDE FOR PREVENTING AND RESPONDING TO CYANIDE POISONING IN THE WORKPLACE 7.

THE HIERARCHY OF CONTROL There are a number of ways to control the risks associated with the use of cyanides. Some control measures are more effective than others. Control measures can be ranked from the highest level of protection and reliability to the Size: KB.

All free cyanide, all dissociable cyanide complexes ( Cyanide),and all strong metal cyanide complexes including ferro-cyanide Fe(CN), ferri-cyanide Fe(CN), and portions of hexacyanocobaltate Co(CN) as well as portions of cyanide compounds containing gold and platinum.

chronic cyanide exposure in humans. However, few data are available on the effects of subchronic exposure to cyanide concentrations that are not acutely toxic.

To address this lack of data, week toxicity studies on cyanide were conducted with male and. female F/N rats and B6C3F. mice administered low doses of sodium cyanide inFile Size: KB. I n contrast to fishes, the effects on corals is much more clear.

In every study I have read, corals suffered bleaching or death depending on the dosage used and the duration of the exposure (Jones & Steven,Jones & Hoegh-Guldberg,and Cervino et al, ). Chapter 5 Sodium Cyanide Hazards to Fish and Other Wildlife from Gold Mining Operations Ronald Eisler -Donald R.

Clark Jr. -Stanley N. Wiemeyer -Charles J. Henny Introduction Highly toxic sodium cyanide (NaCN) is used increasingly by the international mining. The behaviour of cyanide in a landfill and the soil beneath it P.

LAGAS, J.P.G. LOCH & K. HARMSEN* National Institute for Water Supply, PO BoxLeidschendam, The Netherlands *ICARDA, PO BoxAleppo, SYRIA. ABSTRACT The behaviour of cyanide in a landfill and the soil was studied because at several locations in theFile Size: KB.

2%”. Other minor uses of hydrogen cyanide include the “manufacturing of ferrocyanides, acrylates, lactic acid, pharmaceuticals, and specialty chemicals”. The use of hydrogen cyanide as a fumigant is decreasing.8 United States production of hydrogen cyanide in was billion pounds Cyanide from mineral processing: Proceedings of a Workshop, February, Salt Lake City, Utah on *FREE* shipping on qualifying offers.

Cyanide from mineral processing: Proceedings of a Workshop, February, Salt Lake City, UtahManufacturer: Utah Mining and Mineral Resources Research Institute, College of Mines and Mineral Resources, [University of Utah]. The heap leach component of the mine water system must be operated as a closed water circuit under normal operating conditions: in certain jurisdictions, it may be possible for an operation to secure permits to treat and discharge excess stormwater from leach pads, although this is likely to requireFile Size: 65KB.addition of phosphorus as a limiting nutrient to bring cyanide and its breakdown compounds (i.e., thiocyanate, ammonia) down to concentrations acceptable for release to the environment.

This mine is located within 50 km west of the Yellowknife Gold Project. Request 2. Please provide an explanation how leaching of cyanide will mitigate environmental.Effect of metal impurities on adsorption of gold by activated carbon in cyanide solutions / by S. A. N. as an efficient extractor of precious metals from cyanide leach solutions.

depending on the chemical conditions in the solution (11). The chemistry of copper cyanide has beenFile Size: KB.

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