New effective substance for prevention of dust generation in extraction and enrichment of rocks
The production of coal, metal ores, construction materials such as cement raw materials, stone-building materials, building sand, gypsum, clay rocks and many others in Russia, is growing from year to year. The overall production and power growth of the mining enterprises causes the increase of the negative impact of mining and processing production on the environment.
The share of open-pit mining in the overall volume of mining operations is more than 70%. Its significant flaws are considerable violations and dust emissions polluting the working area. The main sources of dust formation are blasting works, drilling, excavation, mined rock transportation, warehousing and others. Dustiness of the air near the mining operations exceeds maximum permissible concentration by dozens of times. High dust loading leads to the increased sickness rate, mortality, considerable work decrement. The main sicknesses are special forms of lung diseases and the high risk group – employees of the enterprises with more than 15 years of work experience in harmful working conditions.
All currently known methods of dust-control are divided into:
1. mechanical dust removal by washing-down, blowing-off, suction by different machines and mechanisms;
2. the mixing of coating materials with cementitious and adhesive additives in order to form in the upper layer with high operational characteristics;
3. surface treatment or impregnation by spreading of linking, adhesive materials and chemical reagents.
Mechanical dust removal does not eliminate the main dust formation source.
The complexity of processing treatment is the drawback the mixing with cementitious and adhesive additives (bitumen).
Short period of validity from 5 to 10 days and low surface setting rate are the drawbacks of dust-control by salts solution.
Currently watering, that considerably decreases air dustiness, is widely used for dust control. However at the temperature of more than 25 °С and relative humidity of less than 50% the moisture evaporates in 20 minutes after watering and air dustiness on the road exceeds maximum permissible concentrations.
That’s why the problem of improvement of sanitary-hygienic labour conditions and environmental safety by prevention of ambient air pollution in open-pit mining is still very urgent.
In the setting of open-pit mining it’s necessary to use such substances, that are characterized by the high rate of wetting, low volatility, low freezing point and low solubility under atmospheric precipitations. CJSC IMC “Rosneftekhim” has developed a customized dust control agent that satisfies the above-mentioned requirements.
CJSC IMC “Rosneftekhim” produces a new dust control agent PHX-1021 that prevents dust generation on mining dumping sites, tailing dumps and roads in iron-ore, coal, construction and power industries.
Dust control agent PHX-1021 is an effective, economical and environmentally safe product for prevention of dust generation in extraction and enrichment of rocks.
CJSC IMC “Rosneftekhim” manufactures the agent in the form of concentrate, water dilution concentration is from 4:1 to 1:1 depending on the processing conditions and the type of dust-producing surface. Recommended consumption of the agent is 2-3,5 liters per square meter, it depends on the density and the type of treated surface, humidity and the ambient temperature. Depending on the specific object and situation one can use stronger or weaker concentrations. The dust control agent dissolves fully even in cold water and is characterized by kinematic viscosity of 70-120 cSt at 20 º C, which guarantees the simplicity of the working solution preparation and its further application. Phx-1021 can be applied from the tank tracks with rotor pump and spray jets or with the help of stationary sprayers.
Dust control agent РНХ-1021 is easily soaked into the treated surface, it forms homogeneous coating. While working with PHX-1021 one does not need to conduct preliminary loosening and flattening of dust formative mass and hold-up the mining and transport equipment. After treating the surface dust control agent forms a flexible, homogeneous and resistant to atmospheric precipitation coating. It is highly durable and resistant to heavy transport equipment for the period of 20-30 days depending on the loading of the treated surface, that guarantees the economic use of PHX-1021.
One treatment is enough for a resistant coating, but if necessary and at high dust level re-treatment is possible within 2-3 days at the lower consumption. It should be noted, that in accord with the consumer CJSC IMC "Rosneftekhim" can produce dust control agent with the freezing point down to minus 15 °С for autumn and winter period.
Dust control agent PHX-1021 has passed a number of toxicity studies in the authorized body of Federal Service on Customer’s Rights Protection and Human Well-being. According to the above-mentioned studies PHX-1021 refers to the 4 toxicity hazard category (low hazard substances) under the Federal Standard 12.1.007. Flash point in a closed cup is above 200 °С and it does not have corrosion activity. Dust control agent PHX-1021 is completely safe for the human health, environment and equipment when properly used, stored and transported according to the instruction and in compliance with the occupational health and safety, described in the products regulatory-technical documentation.
The specialists of CJSC IMC “Rosneftekhim” have conducted a series of experimental and industrial tests of the dust control agent PHX-1021.
The first experimental and industrial tests were conducted on the open-pit coal mine “Korkinsky” of the JSC “Chelyabinsk coal company”. The upper layer of the road in the open-pit coal mine is covered in stone and coal dust, while performing the tests it was treated with PHX-1021 from the tank tracks with spray jets to complete wetting of the road with the consumption of 2 liters per square meter. The results have shown that dust control agent is easily soaked into the treated surface; it binds the stone and coal dust and considerably decreases the dust formation due to the works of trucking for the period of more than 20 days. The results of dust removal, conducted on the open-pit coal mine “Korkinsky” are described in the article by Marina Morozova, that was published in the newspaper “Chelyabinsk worker” on the 19, June 2012.
Also experimental and industrial tests were conducted at the JSC “Vishnevogorsky ore mining and processing enterprise”. Its specializes in extraction and production of feldspathic materials. Given the situation there is a necessity of the nonstop watering of roads for the period of more than 25 days, a resulting flexible coating is resistant to the heavy transport equipment, it doesn’t soak and lose the binding properties under atmospheric precipitation. The treatment allows to cut down expenses for the road treatment considerably, to boost productivity owing to more effective road traffic and to keep the level of dust generation below normal for a long time.
In the result of tests it is safe to say that dust control agent PHX-1021 is a new, highly effective, economic, environment safe product for prevention of dust generation in extraction and enrichment of rocks. PHX-1021 has the following positive characteristics:
- effective dust-binding for the period of 20-30 days by a single treatment;
- it covers the treated surface with a flexible, durable coating resistant to heavy transport equipment, exposure to atmospheric precipitation;
- it is safe for man, environment and equipment;
- simplicity of the working solution preparation and its application on the dusting surface, the processing technology is similar to the process water irrigation;
- technical support by specialists of CJSC IMC "Rosneftekhim" at all stages of dust control agent application.