Safety

Ferrocyanide Toxicity

ferrocyanide-toxicity

It is generally agreed that the ferrocyanide ion is of a low order of oral toxicity, even in relatively large dosage. Kobert states that potassium ferrocyanide in alkaline solution is nontoxic. In Precis de Toxicologie it likewise is asserted that this salt is nonpoisonous and that it is useful as a diuretic. There is recorded a case of ingestion of a rather sizable dose (30 grams) of potassium ferrocyanide by a man aged 52 which caused serious, but apparently not critical illness. The patient suffered damage to the kidney tubules with marked albuminuria, appearance of casts, and prolonged disturbances of concentration ability. The poisoning was said to be due to the ferrocyanide ion and not to any liberated hydrogen cyanide.

The slow intravenous injection of 5 percent sodium ferrocyanide solution administered to children and adults in clinical tests was without toxic effect. Glomerular function was studied in 45 normal children and adults and in 70 cases with glomerulonephritis, hypertension, and tonsillitis. The results indicate that the quantity excreted by the kidneys is independent of the volume of the urine and is greater than 25 percent in the first thirty minutes.

No case of contact ….Read more

Lethal Dose of Cyanide

The chemistry of cyanide solutions is complicated because the cyanide ion forms compounds and complexes with many elements. Some cyanide species are highly toxic whereas others are relatively inert and harmless. Molecular hydrogen cyanide (HCN) is the most toxic form of cyanide. Under most conditions, HCN exists as a gas which readily dissipates or reacts with the environment to form less toxic or nontoxic forms of cyanide. Thus HCN is an ephemeral toxin, and many naturally occurring geochemical processes reduce the HCN concentration of a heap system with time.

As discussed below, free cyanide includes the two species, ionic cyanide (CN~) and molecular hydrogen cyanide. Free-cyanide toxicity in man, mammals, and aquatic species is well documented (Doudoroff, 1976; Ecological Analysts, 1979; Towill et al., 1978). The lethal doses for NaCN reported for human adults vary with the type of exposure as follows:

  • One to three mg/kg body weight if ingested;
  • One hundred to 300 ppm if inhaled; and
  • One hundred mg/kg of body weight if absorbed.

Acute toxicity of free cyanide to freshwater invertebrates ranges from 0.028 to 2.295 mg/1, depending on species and test conditions. Generally, free-cyanide concentrations greater than 0.1 mg/1 are expected to kill sensitive species in freshwater or marine environments ….Read more

How to Extinguish a Mine Fire

In the anthracite fields of Pennsylvania, mine fires occur with more or less regularity and their existence is an ever-present hazard in coal mining. In all probability 90 per cent, of the mine fires can be ascribed directly or indirectly to the ordinary miner’s open lamp. Other causes may be smoking, electrical installations, gas explosions, gas feeders, and the communication of fire to the outcrops from ash dumps, culm banks, timber and brush fires.

Fires in pump rooms, engine rooms, and barns have been largely eliminated as a result of the Act of Assembly, approved June 15, 1911, which provides that all inside buildings, including engine rooms, pump rooms, barns, etc., shall be constructed of incombustible materials. Smoking of pipes, cigars, and cigarettes should be prohibited in the mines and too much care cannot be exercised in preventing fires by enforcing all rules designed for that purpose. Mine fires that involve underground fighting are invariably dangerous, and all fires, irrespective of the method pursued in extinguishing them, involve property loss and expense.mine fire

Each fire generally presents a more or less original problem, dependent on the particular conditions. Generally mine fires may be divided ….Read more

Underground Mine Water Management & Mine Roof Support

2018 02 26 1652In addition to the operational issues of dust control, confined spaces electrical dangers and poor visibility that we’ve discussed in the previous topic there are two other dangers that are every present in underground environments. These are risks due to rock fall and due to water in flow. In this topic, we’ll have a look at how these are managed, when underground openings are created, it inevitable that loose fragments will remain barely attached to the rock faces. In some cases, these are small and isolated and unrelated to the overall stability but in others they may involve some or all of the rock surrounding the opening. In module two, you were introduced to the rock and rock mass characteristics that are important to the design and construction of underground openings. In this topic we’ll have a look at how these relate to underground mining. The most common situation leading to loose rocks in an underground mine is that of over break during blasting. Ideally, a blast will break up the rock you want to remove but not affect the rock you want to leave behind. Unfortunately, this easier ….Read more

Underground Mine Safety

Underground mines are inherently dangerous environments considering both illness and accidents there are around one million work related deaths around the world every year. The mining industry takes safety very seriously with an aspiration goal of zero fatalities. The safety of workers must always be of primary importance in any mining activity. Hazards in underground mining can be effectively managed to allow operations to be carried out with acceptable safety but there are many things to consider. In the topic we will look at the safety issues related to underground mining and how these are addressed.There are major safety risks associated with underground mining related to operational and technical aspects and these include; risks due to poor visibility, risks associated with dust and gas, operation of machinery in confined spaces, electrical danger and technical aspects including rockfall and water inrush. Poor visibility in underground mines can arise due to darkness, short lines of sight and dust concentration. Mines are full of sharp blind corners and being an echo environment sound cannot be relied upon to tell where machinery is operating or the direction in which it is moving. Poor visibility risks can be managed by establishing and following well designed ….Read more

Safety in Open Pit Mining

Welcome back to the surface mining model. In the previous topic, we learned about different types of surface mining operations, about equipment, about different methods that are commonly used to extract coal or different ore deposits. It’s not difficult to understand that mining is one of the most dangerous working environments in the world and in this topic, we will go through some of the main safety issues that we are facing when we work in this environment.

The International Labour organisations is a United Nations agency that sets guidelines of minimum safety requirements for working in a mining environment. The objectives of the safety measures are: the protection of workers from safety and health hazards and the minimisations of risks in their working area, the prevention and reduction of incidents and severity of illness or injury, the training and implementation of safe operating procedures to improve safety and health. The ultimate goal is always to eliminate the risk. As this is not always possible, the safety measures should assist controlling right at its source and minimizing the risk.open pit mining pros and cons

Personal protective equipment should always be used in conjunction with ….Read more

Underground Mine Ventilation

Something that all of the various and mining techniques have in common board and pillar, stoping, caving, long wall mining; is that they take place in underground environments where fresh air does not naturally occur. Not surprisingly, ventilation is a critical importance to the occupational health and safety of underground workers. A continuous supply of good quality air is absolutely essential to allow personnel to breathe, to dilute toxic and flammable gases, to dilute or carry away dust and aerosols and to provide cooling for the personnel and machinery. In this topic we will look at the various issues that arise with regards with people working underground and the principles behind mine ventilation systems. Ventilation is the control of air movement: its amount, its quality and its direction, to maintain a safe and healthy environment in which miners can work. A lack of proper ventilation can cause lower worker efficiency, decrease productivity, increase accident rates and absenteeism. The hazards which are controlled by proper ventilation in underground mines include; low oxygen content, toxic gases, flammable gases, fumes, humidity, temperature, airborne dust and products of combustion. We are going to look at some of these hazards in detail. A mine ventilation ….Read more

Cyanide Poisoning Antidote

In 1910, the Committee of the Chemical, Metallurgical and Mining Society of South Africa, appointed to investigate cyanide poisoning, recommend as an antidote to Cyanide Poisoning the following:

  1. Thirty cc of a 23 per cent, solution of ferrous sulphate.
  2. Thirty cc of a 5 per cent, solution of caustic potash.
  3. Two grams of powdered oxide of magnesium (light).

In every cyanide-room there should be kept three boxes, containing—

  1. A metal receptacle to hold about a pint, and a spoon.
  2. A blue hermetically sealed phial, containing 30 cc of a 33 per cent, solution of ferrous sulphate.
  3. A white phial, hermetically sealed, containing 30 cc of caustic potash.
  4. A packet of oxide of magnesium (light).

Preparation of Antidote

Quickly empty the contents of the blue phial, of the white phial, and of the magnesia package into the metal receptacle, and stir well with the spoon. This should be done as rapidly as possible, as the patient’s chance of life depends on promptness.

Administration of the Antidote

If the patient is conscious, make him swallow the mixture at once and lie down for a few minutes. If the patient is not conscious, place him on his back and pour the mixture down his throat in small quantities, if ….Read more

Underground Mine Fire Prevention

During the winter and spring of 1917, an unprecedented number of underground fires occurred in the Butte district. With one exception, these fires were caused by the failure of electrical equipment, and called attention to the increased fire hazard in underground mining operations occasioned by the extensive use of electricity.

Five local conditions that contributed toward a heavy fire risk were:

  1. The heavy continuous timbering necessary for mine supports;
  2. the strong ventilating pressures in the shafts and main airways;
  3. the subsidence and faulting movements in the country rock, which ruptured cables and displaced trolley and lighting wires;
  4. the strongly acid mine waters, which quickly developed any weak points in the electrical insulation;
  5. oxidation in old stopes containing large amounts of timber.

In the summer of 1917, a comprehensive plan of fire prevention was begun by the Anaconda Copper Mining Co., which involved a thorough and intensive development of the preventive measures then in use. These were as follows: Fireproofing, remodeling and strengthening electrical insulations, extension of underground water system, control of ventilation, maintaining efficiency of fire-fighting crews, and reorganization of fire patrol.

In considering the problems of fireproofing, it was immediately apparent that some method of applying a durable coat of fireproof material ….Read more

Gold Room Security

Very little is documented about Gold Room Security due to the sensitivity of people around it. At the same time, when establishing a new operation it is useful to have a standard security starting point on which to address the issues with directly related to gold room security design fundamentals. This paper will provide guidelines and a ‘prompt’ for the issues to be considered when establishing a new operation. Gold mining invites the inherent problems of vulnerability, threats and countermeasures for the security of gold products. Due to the errors in metallurgical accounting and grade control issues, gold theft may be undetected for some time. Generally, stealing starts in a small way leading to larger theft and at some scale the theft is detected.

by D. Connelly

Historically, the greatest threat to gold security is from internal staff. Typically, when gold is stolen by a person in a position of trust, they have had no previous record of dishonesty. Personal circumstances may change altering ethical values and moral judgement and this is borne out by anecdotal evidence. Sadly, the old proverb, ‘opportunity makes the thief’ is very true. Recently, external personnel have conspired to steal gold, but this is ….Read more

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