Recommended Safe Working Practices. Orica Seismic Products

Transcription

1 Recommended Safe Working Practices Orica Seismic Products

2 Recommended Safe Working Practices Orica Seismic Products October 2008

3 Contents Introduction Handling Explosives 4 Description of Explosive Materials 6 Properties 7 Explosive Safety Fires 9 Static Electricity 9 Radio Frequency Energy 9 Other Communication Devices 10 Lightning 10 Stray Currents 10 Explosive Products Geogel Seismic Gelatin Dynamites 11 Osx 8 Cast Boosters 12 Osx 5 Emulsion Explosives 13 Osd Seismic Electric Detonators 14 Oseis Seismic Electronic Detonators 16 Cordtex Detonating Cord 18 Product Use Handling Detonators 19 Shock, Impact and Friction 19 Preparing Charges 19 Priming Charges 20 Loading Charges 25 Shooting/Detonating 27 Potential Problems Blowouts/Delayed Blowouts 29 Some Factors in Exposure 29 Some Basic Preventions in Exposure 29 Misfires 30 Abandoning a Misfired Charge 31 1 Recommended Safe Working Practices Orica Seismic Products

4 Specialty Applications Proximity to Pipelines 32 Pattern Shooting 32 Surface Shooting 34 Seismic Cleanup 35 Prevention of Blasting Accidents A Summary of Actions for the Prevention of Blasting Accidents 37 i. Storage of Explosive Materials 37 ii. Collection of Explosive Materials and Transportation to the Line 38 iii. Preparation of Charge 38 iv. Handling of Detonators 39 v. Priming of Charge 40 vi. Loading of Charge 40 vii. Shooting 41 viii. Use of Detonating Cords 41 ix. Use of Explosives on Surface 42 Disclaimer 44 Copyright 44 References and Acknowledgements 44 Contents 2

5 Introduction The advice in this booklet is offered gratis with the main objective of keeping seismic workers free from harm as a result of accidents caused by irregular or improper use of explosive materials. The precautions are based on the collective experience of many individuals and organizations, and the advice is given in good faith as representing the soundest safety advice in the use of Orica Explosives. None of the guidelines suggested in this booklet are intended to supersede or countermand any Federal, State, Provincial, Territorial, Municipal and company regulations that must be followed in the use of explosive materials. It is the blaster s responsibility to ensure that all aspects of the seismic blasting operation are carried out in a safe manner. This includes designation of a safe work area, as well as safe procedures for explosives storage, handling, preparing, priming, loading and shooting. Persons undertaking drilling/loading or blasting operations within the seismic industry must be qualified, certified and trained in the following or be under the direct supervision of a person with the following qualification, certification and training: Seismic Blaster Safety Training or local equivalent Minimum 18 years of age (regulatory dependent) Minimum six months experience in seismic blasting operations Ability to communicate effectively in the English language, both orally and in writing (country dependent) Be physically capable of safely carrying out the duties of a blaster Blasters must obtain and maintain a personal log of all blasting work that they have performed, if required by regulations or company policy THE BLASTING AREA is generally defined as the area extending at least 50 meters (165 ft) in all directions from a place where explosives are being prepared or fired, or where unexploded charges are known or believed to be. The Minimum Seismic Industry Safe Distance is 30 meters (100 ft). This is the recognized safe distance for blasting. No one should be within this zone while blasting, including the blaster. The Critical Work Zone being 15 meters (50 ft) in all directions from the shot point, meaning: No smoking No radio transmitting No cell phones/pagers 3 Recommended Safe Working Practices Orica Seismic Products

6 The Critical Work Zone applies 100% of the time to open flame and smoking. Regarding Radio Frequency (RF) Transmitting, the zone applies when the explosive product is not secured within the appropriate magazines. The minimum seismic industry recognized time delay to approach the shot point after firing is 30 seconds or more. This is to protect blasters and helpers (anyone in the blasting zone) from delayed blowouts. The safe work practices discussed in this document essentially set a minimum standard for seismic blasting operations. You should also check with your supervisor as your company may have additional safe work practices that you should operate under. These would include, but not be limited to: Handling explosives Handling detonators Preparing charges Priming charges Loading charges Shooting Remember, one small error with explosives could be fatal to you or others around you! Handling Explosives Explosives used in commercial blasting operations are a combination of various substances and mixtures that produce a rapid exothermic reaction when initiated. The explosive ingredients are either a molecular explosive where the fuels and oxidizers are on the same molecule, such as with TNT or a physical mixture of solid and/or liquid oxidizers and fuels such as in emulsion explosives. A detonation is a specific type of explosion consisting of an exothermic reaction, which is always associated with a shock wave. This shock wave in rock becomes a sound wave travelling through the earth. This is actually the only part of the explosion process of interest in seismic work. A secondary pressure is generated; by the gasses generated in the detonation. This gas pressure, which is usually less than 60% of the strength of the shock pressure helps move rock in blasting applications such as mining and quarrying. The detonation is a self-sustaining chemical reaction that will consume any explosive in its path at a very high velocity. Once initiated, the detonation wave will continue until the explosives are consumed. The reaction generally occurs between 5,000 to 7,500 meters/second (16,404 to 24,606 ft/sec.), virtually instantaneous, with seismic explosives. Introduction 4

7 Explosives are routinely initiated by the shock effect of a detonator or another explosive. Explosives are sensitive to heat, shock (impact), or friction so they must be protected from these things to prevent premature, unintended or accidental detonation. The explosives used for seismic exploration are either of the dynamite-type (nitroglycerine with oxidizing salts and solid fuel components), non-nitroglycerine explosives which; are generally emulsions or watergels and molecular types (Pentolite) which are combinations of ingredients that are individually explosive materials, such as PETN and TNT. Emulsions and watergels are aqueous explosives (water based) which contain fine mixtures of explosive ingredients which are either emulsified to form a mayonnaise like explosive or crossed linked to form a gel like explosive. Seismic exploration with explosive materials is carried out using several techniques. One of those methods is the use of shot holes that are drilled and loaded with explosive materials. When the explosive material is detonated, the resulting seismic waves are reflected or refracted by various geological structures located as deep as several miles below the earth s surface. These waves are detected by sensitive geophones placed on the earth s surface and are recorded on magnetic tapes or other media for subsequent data processing to determine subsurface geological structures. Certain kinds of structures are favourable for the accumulation of gas and oil. Thanks to extensive research and experience, modern explosives are safe when used properly. Standards and precautions for storage and use should be well known and can be incorporated into codes that are understandable, enforce able and effective. During seismic exploration a blasting machine sends an electrical signal to the detonator, which is sufficient to activate it. The detonator explosion, in turn, initiates an explosion of the main explosive charge. Detonation of an explosive charge produces a shock wave with a sudden release of hot gases with four common effects: Fragmentation of material Displacement of material Vibration of ground (seismic) Concussion (air blast/noise) When incorporating the use of explosive materials into a seismic operation, careful consideration must be given to the product type, characteristics and long-term implications in the event of a misfire. Different explosive and detonator types are better suited to different data acquisition requirements, work site conditions, and terrain. Orica can assist in providing technical knowledge to help determine the best product for the seismic operation. 5 Recommended Safe Working Practices Orica Seismic Products

8 Description of Explosive Materials Detonator A seismic detonator is a small metal tube with two wires that emerge from a plug. These wires may be twisted together or encased in a shunt to ensure that the circuit is closed in the case of Electric Seismic electric detonators or supplied unshunted in the case of Oseis electronic detonators. Explosive Charge Seismic explosive charges may be in a strong rigid package or plastic cartridge. They can be brightly coloured or wrapped in heavy brown paper. Explosives are produced in a wide range of strengths and detonation velocities. Detonating Cord A small component of seismic work makes use of reinforced detonating cord. This is a strong cord, which can be made of various materials such as braided textiles, waterproofing compounds and plastics with a slim explosive core. Explosive products used in conducting seismic operations are expected to function as per Orica specifications if handled and stored properly. Every shot point that is drilled and loaded is intended to detonate. The way explosives are handled contributes significantly to the preven tion of misfired charges. To reduce the probability of a misfire, the following are suggested: Always follow Orica s recommendations for the safe use of product and its limitations, (Orica best practices) Never handle or use explosive materials unless qualified, trained and certified or under the direct supervision of a person who is qualified, certified and trained Always be completely familiar with the required safe work procedures and regulations for the area in which you are operating Never investigate the contents of a detonator Never pull wires, coupling device, plastic tubing, or detonating cord out of any detonator Never take apart or alter the contents of any explosive material Never expose explosive materials to sources of heat exceeding 66ºC (150ºF) or to an open flame, unless such materials or pro cedures for their use have been recommended by the manufacturer Never strike explosive materials with, or allow them to be hit by, objects other than those required in loading Never subject explosive materials to excessive impact or friction Introduction 6

9 Explosives should never be struck, thrown, dropped, kicked, or otherwise subjected to any form of impact, shock or friction. The results of impact testing on explosives can vary. A negative response in a given number of tests is no guarantee that a positive response cannot eventually be obtained. Whether in cases or as individual cartridges, explosives should not be shocked in any manner. Individual cases of explosives should never be slid across a floor. This applies friction to the bottom of the case; which could be disastrous with some forms of explosives in the event that leakage has occurred unnoticed to the point where the bottom of the case is affected. This could occur if explosives have undergone several extreme temperature cycles (i.e. seasonal changes). This usually applies to explosives several years old. In the event that you observe any signs of leakage or liquid on explosives, the on-site supervisor should be notified. Any liquid observed is almost always water of condensation, but it is best to work safe. If nitroglycerine (NG) is suspected to have contaminated a storage or transportation area, the area should be treated with NG-destroyer under the supervision of the manufacturer or distributor. NG-destroyer is a mixture of materials that when applied to a contaminated area neutralizes the explosive effects of the NG. Explosives can be destroyed, if necessary, by burning or by detonation. There are very specific procedures for this. Unwanted explosives should only be disposed of by, or under the supervision of an experienced blaster. Contact your Orica explosives supplier for technical recommendations regarding product destruction. Properties For general use, explosive products should: Remain intact and sensitive during storage and use Not freeze or break down chemically (i.e. dissociate) under normal temperatures Be suitably packaged for the intended use Be safe to handle, transport and store Upon initiation, detonate properly Possess the following properties: adequate strength for the intended use high velocity of detonation under high hydrostatic pressure suitable density for the particular application adequate water protection minimal fumes produced, particularly in confined areas long shelf life under severe climate conditions Note: Although some seismic emulsions are designed to break down over time, they must never be intentionally abandoned without proper regulatory documentation. 7 Recommended Safe Working Practices Orica Seismic Products

10 Seismic explosives have some unique requirements: Products must be supplied in a strong rigid package or cartridge which will not collapse when pushed to depth through mud or sand Water resistance must be particularly good especially under hydrostatic pressure of a column of water for extended times before firing Products must be capable of detonating at full velocity while under hydrostatic pressure The rate of reaction, known as velocity of detonation (VOD), should be at least 5,000 meters per second, (16,404 ft per second) Explosives must never be knowingly abandoned anywhere, anytime, for any reason. This is a serious offence!! If you find abandoned explosives, do not touch them. Contact your supervisor or the party manager who will notify the appropriate authorities. There are reporting requirements for misfired/abandoned holes specific to Federal, State, Province, County, Territory etc. It is the responsibility of each individual company to maintain records of misfires/abandoned holes. Introduction 8

11 Explosive Safety Explosives are sensitive to heat, shock (impact), or friction so they must be protected from these things to prevent premature or accidental detonation. Fires A detonator involved in a fire will almost certainly explode; this result from the effect heat has on the explosive components inside a detonator. In normal use it is heat from the internal firing mechanisms within the detonator that initiates the base charge. Because detonators are sensitive to elevated temperatures not normally seen in handling and storage they should not be exposed to fire. Static Electricity The most likely source of an accident with electric detonators in seismic work is static electricity. Everyone develops static charges on their body, which can be released at any time by touching a conductor of electricity. The seismic detonator is protected from static charges to a certain extent by a preferred static discharge-path inside the detonator. However, the surest way to prevent accidental detonation of electric detonators by static electricity is to keep the legwires shunted (i.e. wires touching, circuit closed, etc.). Since static electricity is the most likely cause of an accident, you should take precautions to avoid static build up. Here are six points to keep in mind: Wear only natural fiber outer clothing. Do not wear synthetic outerwear, such as polyester that helps generate and hold static electricity Ground yourself frequently by touching clean metal surfaces. Always do this immediately before handling detonators Avoid friction. Never let lead wires slide through your hands Never put detonators in your pockets Never throw legwires as they could pick up static charge in the air Never handle detonators during severe dust, snow or electrical storms Radio Frequency Energy Detonators can be initiated by radio frequency transmission in the vicinity of the detonator. Tables of distances are available in all regulations, relating transmitter power (i.e. watts) to safe distances from detonators. The best rule in seismic is to avoid all radio transmission when handling detonators. In addition, you can minimize the possibility of radio transmission problems by keeping detonator legwires close to the ground to avoid forming an antenna. Keep the doors of portable containers closed when not in use. Upon the approach of a vehicle, cease handling detonators until you are satisfied that the occupant(s) are not transmitting on any radio or cell phone and that radios and cell phones are turned off. 9 Recommended Safe Working Practices Orica Seismic Products

12 Note: Please refer to the IME Safety Library Publication 20 on RF when working with detonators on or near roads or road allowances and post appropriate warnings. Other Communication Devices The licensed blaster on-site controls a blast area of 50 meters (165 ft) around the point where explosive devices are being prepared for firing. Therefore, no low wattage transmitting or receiving devices shall be within this 50 meter (165 ft) area even if they are shut-off. This includes cellular phones, pagers and GPS vehicle navigation systems. Lightning In view of the intense electrical energy associated with lightning in an approaching thunderstorm all explosive work should cease. Workers should remove themselves to a safe area until the storm has passed. These storms can produce enough energy to pose a serious hazard by the threat of lightning hitting the ground near the explosives and potentially initiating them. This recommendation applies for all types of seismic detonators and explosives. Stray Currents Stray currents can be avoided by making sure that detonator leads, do not contact electrical conductors. By far the most important rule when working with Seismic electric detonators is: KEEP YOUR SHUNT ON! Always ensure that legwires are touching and that good contact will be maintained until you are ready to test or shoot. As long as wires are shunted, the circuit is closed and there is a minimized chance of accidental initiation. Explosive Safety 10

13 Explosive Products Geogel Seismic Gelatin Dynamites High Velocity Seismic gelatins are specifically formulated to withstand high hydrostatic pressure and provide both excellent water resistance and lengthy storage periods. These products may be packaged in either paper or plastic cartridges. The plastic is designed to increase the life of the product in the borehole if not punched. Explosives containing nitroglycerine (NG) may cause headaches for some people if vapours are inhaled, or if the substance contacts exposed skin. Always handle explosives in well-ventilated areas and use protective gloves. Allow NG magazines to ventilate for a minimum of 15 minutes prior to entering. Other health hazards, which can be associated with a detonation, are the yellowish red brown nitrous oxide fumes that can be harmful, if inhaled. Always ensure the cloud has dissipated before approaching the shot hole. This is usually more prevalent during blowouts. Geogel Orica s NG based seismic explosive, Geogel is a gelatin dynamite. It has very good water resistance in plastic and stores well at most temperatures and humidity s. Density is 1.43 g/cc and velocity of detonation is over 6100 m/s (20,000 f/s) even under high hydrostatic heads. It is specially formulated to allow punching with relative ease at very low temperatures. Check Orica s product data sheets for recommended shelf life for storage. Geogel comes in two forms: Geogel FAST-LOK is packaged in rigid plastic shells with wide threads, which can be threaded together to construct larger charges and spiral wound paper. It is available in the following sizes: kg (0.28 lb) Spiral wound paper 0.25 kg (0.55 lb) Spiral wound paper 0.5 kg (1.1 lb) Spiral wound paper 1.0 kg (2.2 lb) Spiral wound paper 2.0 kg (4.4 lb) Spiral wound paper 2.0 kg (4.4 lb) Fast-Lok Plastic It is available in 60 mm (2³ 8 in) by 2.0 kg (4.4 lb) Fast-Lok plastic shells, suitable for coupled charges in standard augured holes. Geogel products are reliable under the most severe temperatures and hydrostatic pressures. Geogel can be detonated in tight patterns or in closely spaced holes and shot sequentially with no adverse effect on the charges in adjacent holes. To preclude sympathetic detonation when using Geogel, minimum separation distances are recommended. 11 Recommended Safe Working Practices Orica Seismic Products

14 Charge Size Separation 1 kg (2.2 lb) 0.8 m (2.6 ft) 5 kg (11 lb) 1.4 m (4.5 ft) 10 kg (22 lb) 1.8 m (6 ft) 20 kg (44 lb) 2.3 m (7.5 ft) 50 kg (110 lb) 3.3 m (11 ft) These distances allow for ground conditions, but angle of drilling could cause significant error in the small distances between charges. Osx 8 Cast Boosters An explosive charge composed of a cast mixture of explosive materials, such as TNT, PETN, RDX or HMX that may contain aluminum or other constituents depending on the formulation of the product. The cast boosters, in paper or plastic shells, have a long shelf life when properly stored in approved magazines. The charges have extended exposure life (in a borehole), which can be reduced by degrading technologies. Osx 8 L The Osx 8 L series of seismic explosives are specifically designed as a consistent, reliable high-energy source for seismic exploration applications and consists of a plastic shell filled with the required mass of cast molecular explosives. The modular plastic shells provide a means of coupling the boosters together. The sizes available include 0.5 kg (1.1 Ib), 1.0 kg (2.2Ib), 2.0 kg (4.4Ib) and 2.5 kg (5.5Ib). Twin longitudinal tunnels are cast into the explosive to accommodate conventional Electric Seismic detonators or Oseis electronic detonators. Figure 1: Geogel Figure 2: Osx 8L Cast Boosters Explosive Products 12

15 Osx 5 Emulsion Explosives Water-in-oil emulsion explosives consist of minute sized droplets of an aqueous solution of inorganic oxidizer salts that are surrounded by a very thin layer of a continuous oil phase medium, which is stabilized with an emulsifying agent to prevent liquid separation. The outer layer of oil provides excellent water resistance, which is further improved; by the thick spiral wound paper, plastic film or plastic shell. Emulsion explosives generally have a shelf life of one to two years for inventory purposes after which time they will begin to degrade. Check Orica s product data sheets for recommended shelf life for storage. The sensitivity of emulsions is dependent on either a chemical sensitizing ingredient or the incorporation of voids. These voids are either normal air, gas or hallow micro spheres. The explosive properties are entirely dependent on the chemical ingredients of the emulsion. The oxidizer is in the form of very small (micron-sized) supersaturated droplets surrounded by an oil/wax blend and stabilized by surfactants. Ammonium Nitrate is the major ingredient in the oxidizer solution. There are three mechanisms that will desensitize emulsions. The first is crystallization, which will occur slowly under all conditions of temperature and temperature cycling. The other two will occur when loaded in wet conditions. When exposed to water, the emulsion will slowly absorb water (analogous to osmosis biological systems); at some water level in the 20% range, the emulsion will become insensitive to a detonator. At the same time, the water will leach the oxidizer solution out of the emulsion, which will also desensitize the emulsion. The time taken to desensitize will depend critically on the conditions in the hole and the integrity of the packaging. Magnagel (Osx 5) A safer alternative to traditional dynamites, Magnagel (Osx 5) is an emulsion with very low sensitivity to shock. Since Magnagel (Osx 5) contains no PETN-TNT, no nitroglycerin or related nitrate esters, and no other self-explosive ingredients of any kind, it is unquestionably the safest product on the market. The emulsion detonates solely because of the manner in which the oxidizers and fuels are intimately combined and stabilized during manufacture. This product is packaged in rigid plastic shells to withstand the toughest loading situations. The Fast-Lok shell design is available in three sizes, plus an additional two sizes in the straight plastic shells. This combination of sizes makes it easy for the crew to deliver any desired charge weight. With a density of 1.18 g/cc and a velocity of detonation of 5400 m/s (17,700 f/s) Magnagel (Osx 5) performs similar to seismic dynamites. Figure 3: Magnagel 13 Recommended Safe Working Practices Orica Seismic Products

16 Magnagel (Osx 5) is available in the following sizes: kg (0.28 Ib) Plastic 0.25 kg (0.55 lb) Plastic 0.5 kg (1.1 lb) Fast-Lok Plastic 1.0 kg (2.2 lb) Fast-Lok Plastic 2.0 kg (4.4 lb) Fast-Lok Plastic The shock pressure required to break the glass micro balloons is about 500 psi (3400 kpa). If Magnagel (Osx 5) must be shot sequentially, minimum separation distances should be applied. Charge Size Separation 1 kg (2.2 lb) 5 m (16 ft) 5 kg (11 lb) 6.5 m (21 ft) 10 kg (22 lb) 8 m (26 ft) These distances allow for variance in ground conditions, but it may be necessary to allow for the effect of drilling off-vertical holes. Osd Seismic Electric Detonators A seismic electric detonator has a small metal tube sealed at the open end by a polymer plug. Two wires emerge from this plug. These are the legwires, usually in the form duplex wire (two wires attached together). The ends of the legwires are placed together so that they are shunted (touching). The bare wires may be twisted together or in contact with each other and encased in a shunt material to ensure that the wires are electrically in contact and the circuit is closed. Figure 4: Osd Seismic Electric Detonator Inside the detonator, the wires are joined by a bridge wire; similar to the filament in a light bulb. The bridge wire is located in either a loose initiating charge or in a more compact format called a match head where the initiating charge is coated over the bridge wire similar to a match head. When current is passed through the detonator leads, the bridge wire heats up to ignite the initiating charge of the match head. The flame front from this ignition then initiates detonation of the primary charge and then the base charge. This entire sequence of events usually occurs in one millisecond or less. Explosive Products 14

17 Figure 5: Conventional seismic electric detonator cross section The total explosives content of most seismic electric detonators is less than one gram but they are usually considered high strength detonators capable of initiating detonator sensitive explosive charges. When the base charge is detonated inside a cartridge of explosives, it sends out a shock wave, which causes the explosives to detonate. Shock pressure and heat are the main effects which initiate the reaction in the explosives. To provide an accurate time break signal at the recording instrument, it is essential there be minimal time lag between breaking the bridge wire of the detonator and the detonation. Seismic electric detonators are designed to meet this requirement. Other features important for seismic work include: Excellent water resistance under high hydrostatic pressures and a long in-hole storage Reliable performance unaffected by extreme temperatures Design features to minimize static electricity hazards Shunted legwires to help protect against stray electric currents High strength base charge for reliable initiation of explosive charges Corrosion resistant aluminum shell to withstand prolonged in-hole exposure Heavy gauge legwires for rough loading conditions Polymer legwire insulation designed specially for use at very low temperatures Bright colored insulation for high visibility Even when the detonators cease to function with an electric impulse, the explosive compositions will remain as a potential hazard and should be handled appropriately. 15 Recommended Safe Working Practices Orica Seismic Products

18 Oseis Seismic Electronic Detonators The communication capability of Oseis electronic detonators provides a security feature not found in standard electric detonator technologies. Oseis detonators can communicate specific information about the status of the detonator either prior to loading or post loading the detonator into a blast hole. The communication features of the system offer the ability to interrogate the entire system prior to charging and firing a blast. The Oseis detonator system uses digital communication protocols, blast keys, and logic circuits that can prevent accidental initiation due to operator error or unauthorized use. These features provide a higher level of blast site security and can prevent misuse of the product. The detonator incorporates additional internal components designed to provide increased protection against accidental initiation from extraneous electrical energy (static, stray current, radio frequency, etc.). Unlike a standard electric detonator, the igniter or firing device inside an Oseis detonator is physically separated from the leads by a circuit board or electronic assembly. It is because of this design difference that traditional safety testing equipment such as a blaster s galvanometer as well as shunting practices cannot be applied to electronic detonators. Shunting however does not cause any complications in the use of electronic detonators and the field recommendation to always shunt still applies. Refer to the Institute of Makers of Explosives (IME) Safety Library Publication 12 (SLP 12) for the definition of shunting and its applicability to both Electric and Electronic detonator systems. Figure 6: Conventional electric detonator and electronic detonator cross section Explosive Products 16

19 Oseis The Orica Seismic Electronic Initiating System, Oseis, consists of electronic detonators, Oseis Tester and Oseis Shooter control equipment with trigger interface and software. The system was designed specifically for geophysical exploration and can be used for both single and pattern firing applications in challenging environments. The Oseis Detonator is a high strength, super accurate electronic detonator capable of in field programming of delayed or instantaneous firing times. Through its capability of two-way communication the detonator functionally can be checked via the control equipment anytime from loading to firing. Protection structures built into the electronic circuitry provide a high level of protection against stray current, over-voltage, static electricity and electromagnetic induction not present in conventional electric detonators. Figure 7: Oseis Detonator The Oseis Tester is a multi function device used during loading to perform detonator function, identification and positioning tasks. The Oseis Tester checks for full detonator function, including measurement of any current leakage, and displays user warning messages. The Oseis Tester reads and stores the unique detonator identity number (Det-ID) to memory and allows for entering line and shot point location. Figure 8: Oseis Tester, Oseis Shooter and Oseis Trigger Cable 17 Recommended Safe Working Practices Orica Seismic Products

20 To fire the shot, the Oseis Shooter is connected to the conventional seismic shooting system via the Oseis trigger cable. The Oseis Shooter is protected by a personalized identification number (PIN) to prevent use by unauthorized personnel. Oseis Detonators can only be programmed and fired by Oseis Shooters, which provide the required firing energy and digital information. The final firing command to the Oseis Detonator is given by the Oseis Shooter upon receipt of a dedicated trigger signal. The trigger signal is sent by the firing command from a conventional seismic shooting system. The time between recept of the trigger signal to the detonator firing is a constant 20 ms +/ ms. Oseis software is available as an information management system for explosives loading and shooting operations. The software can provide the ability to track operational status by reconciling detonator testing history with loading location via imported survey and shooting plans. It can provide the ability to confirm and report blasthole shooting and final explosive consumption. This information can be integrated into customer management systems or provide additional quality control and regulatory compliance documentation. Cordtex Detonating Cord A small proportion of seismic work makes use of a reinforced detonating cord, ranging from grains/foot, ( grams/meter). This is actually a very physically strong cord made of braided textiles and plastics with a slim PETN explosive core. Cordtex detonating cord is typically used to initiate explosive charges directly when the shot point is closer than 60 m, (196.8 ft) from power lines. Other reasons for using detonating cord include client requests, landowner concerns and environmental considerations. The detonating cord is initiated at or just beneath the surface by a short length Seismic Electric detonator attached to the cord. The reason detonating cord is used near power lines is to avoid having long lengths of copper wire being thrown up onto the power lines in the event of hole blowout. Sometimes the detonating cord is used in surface blasting to initiate the charge (Poulter Method). The detonating cord used in seismic blasting operations detonates around 6000 to 7000 meters per second (19,700 to 23,000 ft/sec). Cordtex detonating cord has a very long shelf life if stored properly (5 to 10 years). PETN (Pentaerythritol Tetranitrate) is the molecular explosive used in most detonating cords and is essentially insoluble in water. Water will desensitize PETN but it is still capable of detonation if a strong initiator is used. For example if an end of detonating cord is allowed to become wet it may not initiate with a detonator placed along side of the detonating cord at the wet section. If a dry section of the detonating cord is detonated it will shoot through a wet section of the cord. The plastic protective coverings are designed to provide a long service life under a variety of conditions. Explosive Products 18

21 Product Use Handling Detonators Seven conditions which could cause accidental initiation of a seismic detonator include: Shock (impact) Heat Friction Static electricity Radio frequency energy Lightning Stray currents Shock, Impact and Friction Shock, impact and friction may be applied to and prematurely detonate detonators by tampering with the metal tube of the detonator (i.e. hammering, prying with sharp tools, etc.). Another potential means of applying friction would be pulling the legwires out of the detonator. This may also cause accidental initiation. Detonators must never be abandoned anywhere, anytime, for any reason! There have been many accidents with detonators caused by children finding and attempting to open them. All detonators must be accounted for at all times. Preparing Charges Only the number of cartridges of explosives required for a given shot hole shall be removed from the portable container at that shot hole. Explosives and detonators shall remain in the portable containers until the hole is completely ready to load. Only a brass T-bar punch or equivalent is permitted for punching explosive cartridges. Even this T-bar punch should not be used with excessive force; only the force produced by reasonable pushing is acceptable. Never hammer a punch and never use any tools to help force the T-bar punch into the explosive. Steel tools, such as screwdrivers, must never be used for punching. If an explosive appears to be too hard to punch using a reasonable pushing force, do not attempt to heat the explosive to thaw it out. Even at -40 C, explosives should be capable of being punched without resorting to mechanical means. Never place explosives close to heating devices. Notify the on-site supervisor if explosives cannot be punched. Use caution when punching the explosive cartridge as the punch can penetrate through and into your hand. Always use appropriate personal protective equipment (PPE). If there is a requirement to cut cartridges, do so only with a brass knife on a soft surface, away from other explosives (i.e. never in magazines or portable containers). Uncertified helpers, whenever handling, preparing or firing charges must always be under direct visual supervision of the certified blaster. It is an industry recognized practice that no one is allowed to drill alone. 19 Recommended Safe Working Practices Orica Seismic Products

22 Priming Charges Only the exact number of detonators required for a given shot hole shall be removed from the portable container at that shot hole. Primed charges must never be made up in advance. Exposure to a primed charge should be minimized. This can be done by priming the charge; just before loading, and then loading the hole immediately. A primed charge must never be stored anywhere or transported on any vehicle. Before priming, ground yourself and ensure the detonator is securely shunted. Minimum force should be required to place a detonator in the charge. The detonator should be placed in the lower half of the cartridge to avoid contact with the loading pole or stinger point. If there is a capwell, insert the detonator in it. Figure 9: Insertion of detonator into capwell Where required to punch, make the punch-hole only slightly longer than the detonator, and position it so that the exploding-end of the detonator will be in the center of the cartridge. Never punch across the cartridge so that the detonator is actually touching the side. This could result in detonation failures. Figure 10: Improper detonator alignment Product Use 20

23 After priming, the detonator should be secured by making at least two half hitches around the cartridge with the legwires. Never drag primed charges by the legwires. Figure 11: Secured detonator wires around the charge Priming the Charge: Always insert the detonator completely into the hole in the explosive material or capwell Always point the end of the detonator in the direction of the main explosive charge Never punch across the explosive; if the detonator is touching the other side it could result in a detonation failure Use two half hitches with legwire to secure detonator in order to take tension off the detonator when loading Never pull the legwires too tightly. This may break the wires or damage the insulation Never drag a primed charge by the legwires as they may snap or tear slightly, rendering the cap useless or generate a static charge build up Never prime the charge before the shot hole is ready to be loaded Priming a charge is the moment of greatest hazard in blasting! After the shot hole is ready to load, the explosive charges are primed with a detonator. 21 Recommended Safe Working Practices Orica Seismic Products

24 Priming Geogel explosives without a detonator well 1 2 Punch a hole upwards at about 45 degrees on the side of the cartridge about one-third from the bottom end with an approved brass punch. The hole should be only marginally bigger than the detonator. 3 4 Insert a shunted Osd Electric Seismic detonator or an Oseis Electronic detonator into the hole so that the entire casing is submerged in the charge. Secure the detonator with at least two halfhitches around the cartridge with the legwires. 5 Couple any additional charge required, preassembled, on to the primed charge. Couple a drive point onto the bottom end to check any upward movement of the charge. Product Use 22

25 Priming Magnagel (Osx 5) explosives with a detonator well 1 2 Insert a shunted Osd Electric Seismic detonator or an Oseis Electronic detonator into the detonator well at the bottom of the cartridge. Withdraw the Osd Electric Seismic detonator or an Oseis Electronic detonator legwires upwards past the threads and through the single recessed channel provided. 3 4 Secure the legwires with at least two halfhitches around the cartridge. Couple any additional charge required, preassembled, on to the primed cartridge while holding the legwires secure in the recessed channel. Couple a drive point on to the bottom end to check any upward movement of the charge, taking care that the detonator leads remain in the recessed channel if the drive point is being attached to the primed cartridge. Cordtex XTL (48 gr/ft, 10.2 g/m) is used to prime charges that are located close to power lines. 23 Recommended Safe Working Practices Orica Seismic Products

26 Priming Geogel with Cordtex XTL Punch a hole clean through the cartridge about a third from the top and sloping downwards about 45 degrees opposite to the first hole. Thread the Cordtex XTL downwards through the upper hole, then downwards through the lower hole. Figure 12: Securing cord via a knot Tie a secure knot outside the lower end of the bottom hole to prevent the Cordtex XTL from slipping out. Couple any additional charge required, preassembled, onto the primed cartridge. Couple a drive point onto the bottom end to check any upward movement of the charge. Priming Magnagel (Osx 5) with Cordtex XTL Pierce the top of the detonator well and push at least 25 cm (10 in) of Cordtex XTL into the emulsion. Withdraw the Cordtex XTL upwards past the threads through the single recessed channel provided, making sure the cord does not move out of the detonator well. Secure the Cordtex XTL by half-hitching once, just above the level, which the drive point will reach. Figure 13: Secured detonating cord around the charge Product Use 24

27 Note: When using Cordtex XTL to initiate a multiple-shell charge of Magnagel (Osx 5), only the uppermost shell in the hole should be primed. Cordtex XTL should not be fed alongside the charge past the top shell because it may adversely affect the detonation properties of emulsion. Couple any additional charge required, preassemble, on to the primed charge while holding the Cordtex XTL secure in the recessed channel. Couple a drive point on to the bottom end of the cartridge to check any upward movement of the charge, taking care that the Cordtex XTL remains in the recessed channel if the drive point is being attached to the primed charge. Loading Charges Loading Always check each shot hole to ensure it is safe for loading Always take precautions to prevent the accumulation of static electric charges Never force explosive materials into a shot hole Never drop-load a charge Always tamp with non-sparking, anti-static tamping poles and pole extension fittings Never tamp violently Never kink or damage detonating cord, coupling devices or wires of detonator when tamping After the hole is loaded, always test the circuit for continuity and proper resistance using a blasting galvanometer or an instrument specifically designed for testing electric or electronic detonators and circuits containing them Always ensure that the lead wires of electric or electronic detonators are shunted to prevent accidental detonation If the detonator is dead, immediately load another primed charge on top Drillers should demonstrate proper loading procedures to new helpers and instruct them in areas of more difficult drilling formations Drillers must never move up to the next hole leaving the helper to load the shot hole on his or her own All charges require the use of a sand point, to anchor the charge and to prevent movement. A stinger point or overshot and loading pole must be used to push the charge down the hole. 25 Recommended Safe Working Practices Orica Seismic Products

28 Figure 14: Sand point and stringer point / loading pole If loading charges in excess of 10 kg (22 Ib), and loading poles are not required, another method to lower the charge (i.e. binder twine) must be used in accordance with the applicable regulations. After loading, an approved blasting galvanometer or Oseis tester must be used to confirm the continuity of the detonator(s) at each shot point while the hole is still open. If the circuit is open or current leakage is measured in the case of electronic detonators (i.e. broken legwires), immediately load another primed charge on top of the first charge to ensure that the first charge can be detonated. Ensure the actual charge is logged. If the above procedure is unsuccessful then the location of the charge must be appropriately marked and logged. If reloading the hole is not possible use the approved separation distances to locate and drill a new hole. Procedures for misfires should include provisions for smaller sized charges to be used for detonation and proper notification. Note: When using Oseis Electronic Detonators the manufacturer s approved Oseis Tester shall be used at the time of loading (prior to stemming) and after the shothole is stemmed. This is to make sure that the detonator down-lines were not damaged while stemming the shothole. After testing detonators, re-shunt or twist the legwire ends together. Never use a galvanometer or electronic tester that is not approved for blasting. Where it is possible or likely that detonator legwire will break, double cap/prime or use a downline of detonating cord (i.e. insert an additional detonator). All drill cuttings or other material not required to fill the hole must be spread evenly over the ground surrounding the hole unless otherwise dictated by regulations or the permit. A log must be maintained of all loading and shooting conducted. Information should be logged immediately after loading each shot. Product Use 26

29 Figure 15: Explosives inventory log book All hazards must be carefully logged to warn shooters of possible danger. This may include short-drilled holes, explosive cartridges stuck at shallow depth, loose rock at or near surface and any loading poles or other equipment left in the shot hole. Refer to your company s specific procedures for dealing with charges, which have not been successfully loaded. Recognized industry practice is that any shallow holes shall be clearly identified (i.e. flagging, signage or excess detonator wire bundled and visible at the surface). Shooting/Detonating Always fire electric and electronic detonators with firing currents as recommended by Orica Always keep electric and electronic detonator wires or lead wires disconnected from the power source and shunted until ready to test or fire Never attempt to cut and splice leads unless specifically recommended by Orica Never use a blasting machine or firing line that appears to be damaged or poorly maintained Never use blasting machines that are designed for electronic detonators with electric detonators or vice versa unless specifically designed for that purpose Never mix electric and electronic detonators in the same shot hole or blasting circuit Never use other manufacturers equipment with Orica Oseis detonators Never mix electric or electronic detonators from different manufacturers in the same shot hole or blasting circuit Always check that the circuit is complete with an approved galvanometer, blasting machine, or electronic Tester before firing Always ensure legwire ends are clean before connecting Always follow Orica s warnings and instructions for hook-up and firing procedures and safety precautions 27 Recommended Safe Working Practices Orica Seismic Products

30 Prior to hooking up detonator legwires, make sure the following precautions have been adequately dealt with: Check the hole number, line number and check for a pattern Never lean over the hole while hooking the legwires Always discharge static electricity before unshunting the legwires Helper must keep back at least 30 meters (100 ft) Know what the charge depth is prior to arming the Oseis shooter or seismic shooting system Do not transmit by radio from the time that hook-up is started until it is complete and all personnel are in a safe position. This area is considered The Critical Work Zone. Shunts should not be removed or the detonator should not be unshunted until ready to make the final connections. Make sure connecting wire ends are clean. Ensure that the firing line is of clean, insulated and undamaged suitable cable. The line should be laid along the ground with connections slightly elevated to prevent current leakage into the ground. Ensure the circuit is complete, using an approved blasting galvanometer or an Oseis Tester before firing. Always make sure that all personnel are safe from harm before shooting. Assume that the charge may be just under the surface (i.e. a floater) such that dangerous flyrock could be thrown around. Figure 16: Shot hole blowout The industry minimum safe distance from a shot point is 30 meters (100 ft). Never shoot when anyone is less than 30 meters (100 ft) from the hole! Product Use 28

31 Potential Problems Blowouts/Delayed Blowouts Always wait the required time prior to approaching a fired shot hole. Always approach a hole with caution after the charge has been detonated. Be prepared for a delayed blowout. Delayed blowouts may only occur a small percentage of the time, however, the exposure/risk to the blasters (and blasters helpers) is significant to warrant that some basic safe work procedures be created/used by industry. The most obvious exposure is when a blaster (or helper) approaches the shot point, after blasting, in order to trash/clean the shot point. There may be little or no warning for a significant delayed blowout to occur. Some Factors in Exposure Recognize that the critical work zone is 15 meters (50 ft) in all directions around the shot point Recognize that the blaster is directly responsible for the blasting area, which is 50 meters (165 ft) in all directions around the shot point That natural gas pockets form near the surface in some areas That soft, wet or frozen ground conditions can contribute to delayed blowout problems Poor loading procedures, specifically plugging of the shot hole Some Basic Preventions in Exposure That the blaster and helper MUST maintain a safe distance outside the critical work zone, maintaining a minimum distance of 30 meters (100 ft) (from shot point) while blasting That a minimum of 30 seconds after detonation should be observed before approaching the shot point To observe ground conditions, and remember that they may be a factor in delayed blowouts That the helpers must be specifically trained and supervised, while working around the shot point(s) That drill crew(s) be trained and supervised in proper tamping methods, and that additional precautions be taken in areas where further exposure may be a concern 29 Recommended Safe Working Practices Orica Seismic Products