Repumpable bulk emulsion (RPEM): RPEM systems have essentially been designed to extend the advantages of bulk explosives to traditional packaged

explosive areas. These are low cost units for fast accurate loading of small quantities per borehole. Like all bulk explosives all the components are also non explosive and are mixed on the mine bench and loaded directly into the borehole. Typical capacities are 5 to 8 tonnes. Advantages are: (i) suitable for small and intermediate dia.

Boreholes (ii) low cost units. Disadvantage is: not suitable for large blasts.

191. (a)What is the trend of accidents in metalliferous open cast mines in India? Indicate by death rate per 1000 persons. Give also cause-wise classification analysis. Which came contributes the maximum no. of accidents in Mechanized Opencast mines now-a-days? Suggest measures to minimize accidents due to such causes.

(b) What is the share of the other causes in fatal accidents causation in Open cast non-coal mines? Suggest remedial measures to minimize such accidents also.

(a) Currently, due to increased mechanization of the metalliferous Opencast mines of our country more accidents are taking place due to machinery (about 35%) as per statistics published by DGMS the death rate per thousand persons employed in metalliferous Opencast mines was 0.28 in 1987, 0.35 in 1988, 0.20 in 1989, 0.41 in 1990, 0.46 in 1991, 0.33 in 1992, 0.36 in 1993 and 0.26 in 1994. It showed an

increased trend upto 1991 and was on decline slightly in 1992 and 1994. Cause-wise classification of fatal accidents during the period 1987-91 showed that 11 fatal accidents occurred due to dumpers and trucks in 1987, 18 in 1988, 15 in 1989, 16 in 1990 and in 26 in 1991 and this trend remained practically the same during the last three years with marginal decline. Accidents due to fall of sides varied from 7 to 16%

per annum during 1987-91.In mechanized Opencast operations, wheeled trackless transportation machinery (dumpers, tippers, trucks, tractors and trailers) contributes maximum numbers of fatal accidents. Such accidents constitute about 75% of all fatal accidents due to HEMM and 58% of all fatal accidents in Opencast and surface operations. Accidents due to tractors had registered a raising trend the rate of fatal accidents per 1000 dumpers, trippers, trucks etc deployed was found varying from 30 to 40 during the last few years. The analysis revealed that there is hardly any decline worth the name in the trend of accidents due to wheeled trackless transportation machinery. Cause wise analysis (in percentage) of fatal accidents due to W.T.T machinery revealed that contribution of "negligent and unauthorized driving" and

"while reversing vehicles" is maximum (roughly 2 out of every 3 or 4 accidents)."Run over while crossing the road" too took significant toll (about 20%).Location wise percentage of fatal accidents due to W.T.T machinery revealed that only one out of every three fatal accidents occurred in actual quarry operation area(opencast

excavation),remaining about 65% of accidents occur in ancillary surface operations sites; one out of every three fatal accidents took place on haul roads and associated roads(specially near workshops, office complex).Accidents in the stock-yards/sliding had increased (mostly due to over-crowding of contractor's vehicles and the

company's dumpers at the same stock yard).

The following measures are suggested to minimize accidents due to W.T.T machinery:-

(i) Strict compliance with the conditions stipulated by DGMS in the permission U/R 106(2) (b) of MMR1961, provision of A.V.Reversing alarm & spotter to each transport vehicle.

(ii) Formulation and implementation of "code of traffic rules" and "code of practice"

for prevention of injuries to persons engaged in tipping on stockpile dump etc. As per recommendations of the Seventh conference on safety in mines

(iii)Adequate care in selection and training of operators and drivers of dumpers &

trucks. On conclusions of training, competency should be evaluated by a Board constituted by mining company and a competency certificate awarded

(iv)Technical training should be supplemented by "operator's development programme" in which special stress should be laid on "motivation" "perception conditioning" "enforcement of discipline" and "development of good system & work culture". Provision of "substitute" operators to avoid overtime work

(v)To prevent un-authorized driving, a system should be evolved where under the drivers/operators always keep the ignition key and/or cabin key with them through out the duty hours and there after hand over the same to the reliever driver or to a

specifically designated competent person

(vi)In every tractor and trailer combination operators the trailer should have four wheels and separate brake of its own the surface haul roads in mine premises which are frequently used by workers and other persons should have a separate lane for the pedestrians and two wheelers.

(viii)Every mine should be established a system where by loading and unloading operations are not carried on simultaneously at the same place on the stock yard.

(ix)Strict control and supervision of contract vehicles and person who should be adequately trained and made safety conscious by appropriate training schedules and modalities.

(x)Test run of dumpers/trucks should be done only by such fitters of the repair shop who have undergone drivers/operators training and posses competency certificates (xi)Proper design, construction and maintenance of haul road, its gradient, width, bend modulation, drainage, dust suppression and consolidation

(xii)Adequate lighting arrangement

(xiii)Conditioning monitoring vehicle and provision of safety belts to the operators (xiv)Transport arrangement and maintenance crew to the site

(b)Share of other causes are- (i) Fall of sides (about 12%) (ii) Fall of persons (about 12%) (iii) Other machinery (about 11%)

(iv) Explosives (about 9%). Rest due to other causes Remedial measures suggestion-

(i) Maintaining and monitoring slope and dump stability

(ii) Examination of structural stability of heavy machinery by experts before commissioning of major repair and at interval

(iii) Safe and modern blasting practices

(iv) Application of organic principles in designing operators cabin (ergonomics) and but not the least review of management structure vis-�-vis inter disciplinary interface 192. Besides legislative measures, what are the other recent developments in

mine safety movement in our country?

Some of the recent developments in mine safety movement in our country, besides the legislative measures include,

(a) Self-regulation by management: Most of the mining companies in the organized sector have set up Internal Safety Organization (I.S.O) for the purpose. It is headed by a very senior officer and is multi-disciplinary in character.

(b) Participation of workers in safety management: Recognizing that much greater strides in safety can be achieved by participation of workmen in safety programme, the twin instruments of "safety committee" and "workmen's inspector" have been conceived and even given statutory backing.

(c) Role of workers organization: Worker's organizations have been given increasing role to play in the formulation of safety programmes as well as in the review of the implementation thereof. There are several such formal and ad-hoc tripartite committees at various levels and in fact the 'committee" under Sec.12 of the mines act 1952 is a tripartite body.

(d) Vocational and other training: Recognizing the need for safety education to prepare the mine workers to face the challenges of mining, the Mines Vocational Training Rules were framed in 1966. These rules provide for initial refresher and specialized training of mine workers. Besides this, in-house training programmes are organized by mine operators to make workers safety and productivity conscious.

(e) Observance of "safety week" , "safety campaign" etc: During the safety weeks held every year, efforts are made to inculcate safety consciousness amongst workers, Supervisory staff and others by various audio-visual means. Further, by holding competitions among various participating mines, an attempt is made to improve the working conditions. Based on the accident experience, special drives are sometimes launched to focus attention on specific cause group.

Besides these, "Safety Conferences" at national level are held periodically to review the status of safety in mines and adequacy of existing measures in a spirit of mutual co-operation. This body also suggests measures for further improvement in safety. So far, ten such conferences have been held. As an additional incentives National safety Awards (mines) have been instituted by Govt. of India from 1983 on various indices of safety performance like longest accident free period, lowest injury frequency rate and largest percentage reduction in injury frequency rate in the contest year over the preceding two years.

193. What is the purpose of accident investigation? How accident reports and records are significant in accident prevention?

The purpose of accident investigation is to identify and discover the hazardous

conditions, unsafe practices and other weakness in the system responsible for accident causation, so that accidents from similar causes may be prevented. This is

accomplished by -

a) Detailed investigation of each individual accident and dangerous occurrences to discover the causative factors involved.

b) An analysis of the factors found and

c) Recommendation for corrective actions based on the findings of the investigation.

Responsibility of accident causation also needs to be pin-pointed for improved awareness and strict vigilance in future.

Accident investigation reports and records generate a wealth of information on preventive measure provided "root" causes and circumstances leading to each accident/dangerous occurrences are correctly identified and analyzed. Remedial measures are based on such analysis. For example if an analysis of accident record it is found that unsafe or defective design of a machine or system is contributing to accidents or mishaps "engineering revision" of the system is a must to prevent such accidents. If unsafe work-situation or unsafe practices are revealed in the enquiry reports, accident prevention methods may be formulated on the basis of the

recommendations of the enquiry report. Further, recommendations contained in the enquiry reports of major accidents or disasters are circulated to industry for

compliance and eventually incorporated in the statutes as "mandatory" provisions of law. Thus accident investigation reports and records are very significant in accident prevention.

194. How accidents are caused?

CAUSES OF ACCIDENT: Accidents constitute a behavioral problem signifying disintegration in the equilibrium of the individual in relation to the work-situation.

The forces responsible for disequilibrium are mainly drawn from the stress of the work-situation and the psychological character of the individuals involved. As soon as

this field is disturbed due to displacement of a relatively specific situation of the appearance of a new one, the equilibrium is upset causing an interruption or

disorganization in performance. If we analyze the mechanism of accident we will find that accidents are interplay of various factors which can be broken down to some thing like this:-

1) The general psychological factor of the individual concerned as seen in the combination of inherited and acquired characteristics. Recklessness , stubbornness and other undesirable traits of character may be passed along through inheritance.

Environment may develop undesirable traits of character. Both inheritance and environment cause "fault" of persons.

2) A second factor, which may be permanent or temporarily, but which exists in the individual at a moment when he commits a dangerous act which is actualized by nervousness, violence, apathy, aggressiveness and anxiety etc.

3) A factor of convergence which is made up of dangerous act and mechanical and physical circumstance which already existed or which appeared at the time of the act (lighting a match in an inflammable atmosphere)

4) The material factor in the accident corresponding to the reaction of the material (explosion in the mine)

5) The resultant factor; injuries or death to persons in the vicinity.

The mechanism is illustrated below:-

195. What are the two main indices of injury performance? What is their significance?

The two main indices of injury performance are injury "Frequency Rate (F.R)" and injury "Severity Rate (S.R)".These two indices measure the exposure risk in hazardous activities.

FREQUENY RATE: The method of calculation of this rate varies from country to country. In USA, the F.R is no. of accidents per million man-hours worked.

F.R =

No. of accidents x 10⁶

Total no. of man hours worked

This rate is calculated for a period; 6 month or one year. In U.K, Germany, Canada, France, Belgium, Czechoslovakia, Poland and Netherlands, F.R is no of accidents per 1,00,000 (one lakh) man-shifts worked.

F.R =

No. of accidents x 1, 00,000

Total no of man-shifts worked

In India until recently, F.R was calculated as no. of accidents per 1000 men employed.

F.R =

It is also calculated per million tones of output in Coal mines.

But for the purpose of Natural Safety Awards (Mines) introduced from 1984, the average injury rate in the mines of our country is determined as follows:-

The total of the number of persons killed per one lakh mandays multiplied by ten and number of persons seriously injured per one lakh mandays multiplied by three.

Example: In a mine employing on average 200 persons per day, in a particular year three persons were killed and 20 persons were seriously injured. In this mine the average injury F.R will be

[Working days have been assumed as 300 in that year]

Injury Severity Rate (S.R) is the no of man-days lost as a result of accident per million man-hours worked. In case of permanent disability a "Standard" time lost is used and the actual time lost by victim is ignored. e.g. If a man loses a thumb in an accident a time lost of 600 days is made regardless of his actual lost time. This is due to reduced performance. Scheduled charges for disabilities have been prescribed based on Workmen's Compensation Act. For death or other permanent full disabilities equivalent man days lost is 6000 and the days are reduced proportionately according to percentage disability. In other cases of lost time injuries the actual days lost are taken into account. Example: In the same mine quoted before, in that particular year 600 man days were lost besides 3 deaths.

S.R =

The significance of the two indices is the identification of the status of safety performance. These indices make the accident data more meaningful and suited for comparison purposes. The severity rate reflects the "seriousness" of the time-lost accidents. These are therefore very important tools in accident analysis for evolving remedial measures.

196. How serious do you consider is the threat of "NOISE" in mechanized open cast mine? Indicate the generally prevalent noise levels at heavy machinery like shovels, dumpers, ripper dozer, drills, scrapers, graders, front end loader and crushing

and screening plant. Suggest measures to improve condition at the work places in this regard.

Noise pollution has become a matter of concern in mechanized open cast mines because heavy machines like pneumatic drills, dozers, shovels, dumpers and crushing and screening plant etc, in the mine premises emit noise the level of which varies from 80 to 115db(A) having varying degree of adverse effect on the surrounding environment . The adverse effects are: (i) auditory and non-auditory on the health of the workers. (ii) On the operating system of the mine and (iii) on the physical objects.

The auditory effects include temporary/ permanent hearing loss. The noise induced hearing loss is influenced by the frequency and intensity of noise, its bandwidth, duration of exposure in a single day and number of years of working day exposure. It is irrecoverable and cannot be cured by hearing aids. Above an average hearing loss of 25db (A), a person's hearing is said to be handicapped or damaged. Non-auditory effects on health are vasco-constriction, gastro intestinal modification/electro mayo graphic evidence of increased muscle tension, respiratory modification and skin resistance alteration. Besides effect on health, noise has effect on task performance, efficiency, resulting introduced production, increased error rate, annoyance,

distraction, anxiety, low morale, nervous irritability and strain fatigue and interface with speech communication and signal which is possibly the best understood of the non-auditory effect of noise. It interferes with sleep also and may become a factor of absenteeism. The effect of noise one physical object may be structural impairment, property devaluation etc. Therefore noise in the mechanized opencast mine is a serious hazard not only to the health of workers and mine operating system but also causes great environmental pollution in the current standard concept and awareness.

Generally prevalent noise levels in some HEMM :Diesel (in cabin) -92dB(A);

Dumper (in cabin)-80 to 108 dB (A); ripper dozer (in cabin)- 90-106dB (A); Drills (pneumatic)- 105-115db(A); Drill master 85-111db(A); Scraper 85-100db(A);Grader 88-96db(A);Front end loader 85-105 db(A); Crushing and screening plant

80-105db(A)

Measures to improve the condition of the work place: From noise hazard point of view, the condition at the work place can be improved by the following measures individually or in combination:-

i) Noise control at the source which is by far the most cost -effective and positive approach

ii) Control of transmission path

iii) Protective measure at the receiver including reduction of exposure duration, to be adopted in extreme situation when noise control by first two means is impracticable or not feasible.

Noise control implies reduction of the noise level down below the prescribed permissible limits vis-�-vis the exposure time in case of continuous noise or

permitted no. of impacts per day for "impact" or "intermittent" noise, Based on I.L.O code of practice DGMS, vide circular no 18(Tech) of 1975 had recommended

"provisionally" certain standards and guidelines. The danger limit value, in this circular was 90 db (A) above which danger of hearing impairment and deafness might result from an unprotected ear. But recent noise surveys conducted in some mines indicated that persons employed in the vicinity of HEMM were getting exposed to sound levels higher than those recommended in the above circular. Therefore vide

DGMS circulation (Tech) no5 of 1990, immediate steps recommended to be taken to control noise level and afford necessary protection to workers against noise. The suggested noise control measures included "reduction of noise level at source" by engineering design of the machine or equipment and its proper installation and maintenance e.g. damping impact noise, noise insulation by sound absorbing

materials, acoustic barriers or enclosures etc. These measures include control of noise via transmission path also. In situation, where noise control at source or control of transmission path is just not possible, 'effective' personal hearing protection

programme has been suggested in this circular. This program essentially comprises the following constituents:-

i) Assessment of noise level by audiometric surveys in the manner recommend in DGMS circular No 18 (tech) of 1975

ii) Determination of levels of residual protection after implementation of reasonably practicable noise control measures

iii) Selection of protectors to give required attenuation

iv) Workers perception of the consequence of not wearing protector correctly

v) Selection of protector accept to the individual worker for the period of required use vi) Training of wearers

vii) Demarcation of work location where protector should be used

viii) Adequate supervision to ensure protected in an efficient hygienic condition and ix) To reduce, by all appropriate means, the exposure of workers to any excessive noise.

I believe that by adopting the above measures, the condition of the work place may be improved.

197. "Fire on surface heavy machinery is a serious hazard to life and property"

discuss the various causes and effective remedial measure to reduce these hazards.

Currently, increasing mechanization in surface mining, higher mining capacity envisaged, use of high pressure hydraulics, high torque engines, high amperage motors in HEMM accompanied by continuous operation, constant vibration and stress, rugged environment, dusty muddy conditions, malfunctioning and fault, maintenance at times pose serious fire hazards to such equipment. A simple rupture / leakage of hydraulic hose, spilling hydraulic fluid on hot manifolds, or any other hot component of the equipment can cause sudden ignition, engulfing the various

components or entire equipment in flames. Though total elimination of fire hazard is very difficult yet "fire potential" can be reduced to some extent by improved design of

components or entire equipment in flames. Though total elimination of fire hazard is very difficult yet "fire potential" can be reduced to some extent by improved design of

In document 48213-7022 Dgms 1st Class Question Paper (Page 91-101)