By Colin Rice
All drilling operations involve lifting and lowering loads but different types of drill rig lift and lower loads in different ways depending upon the design of the drill rig and the nature of the operation. Every major mining company has identified lifting operations as a fatal risk and so a very clear understanding of the legal requirements applicable to lifting operations is of critical importance for persons involved in the exploration drilling industry.
What regulations govern hoisting operations?
Both the Mine Health and Safety Act (MHSA) and the Occupational Health and Safety Act (OHSA) contain regulations relating to lifting operations and so we have to carefully examine both Acts to determine what regulations apply to exploration drilling operations.
Chapter 8 of the Regulations of the Mine Health and Safety Act contains Lifting Equipment Regulations (Section 8.5) and Section 18 of the Driven Machinery Regulations of the Occupational Health and Safety Act addresses lifting machines and lifting tackle. In neither Act are drilling operations explicitly mentioned and so, we must very carefully extract which of the regulations apply and then interpret the meaning of the regulations in an exploration drilling context.
Before we discuss the regulations, it is important to remember that in terms of Section 103 of the MHSA, the OHSA regulations apply where the MHSA is silent. This presents us with a couple of significant complications because there are a number of very onerous requirements in OHSA that are not in the MHSA regulations. The implications of these OHSA regulations are very serious and mean that potentially many of the drill rigs operating in South Africa do not comply with legal requirements.
Chapter 8. Machinery and Equipment
8.5 Lifting Equipment Regulations
"Lifting equipment," means any equipment or machine or arrangement of equipment or machines intended or used for the lifting, lowering, suspension, or moving in suspension of any person or load.
"Lifting tackle," means any attachment, including anchoring points, used to secure lifting equipment or a load to lifting equipment.
(1) The employer must take reasonable measures to ensure that no person is injured due to the failure of any lifting equipment or lifting tackle as a result of-
(a) incorrect installation; or
(b) insufficient maintenance.
(c) incorrect design for the intended application;
(2) The employer must take reasonable measures to ensure that the installation, use (including the transport of persons), maintenance, inspection, testing and keeping of records of lifting equipment and lifting tackle are done in accordance, with a written operating procedure prepared and implemented for that purpose.
(3) The employer must take reasonably practicable measures to ensure that -
(a) only lifting equipment and lifting tackle with a minimum factor of safety of four (4) is used;
(b) lifting equipment and lifting tackle are not used beyond their design capacity; and
(c) the safe working load of any lifting equipment and lifting tackle is conspicuously and clearly marked or indicated thereon.
(4) Notwithstanding regulation 8.5(2), the employer must take reasonably practicable measures to ensure that the following lifting tackle has a minimum factor of safety of-
(a) ten (10) for natural fibre ropes;
(b) six (6) for steel wire ropes, man-made fibre ropes and textile webbing; and
(c) four (4) for high tensile steel chains.
(5) The employer must take reasonable measures to ensure that only persons authorised in writing by the employer to do so, operate lifting equipment and lifting tackle
(6) The employer must take reasonably practicable measures to ensure that the lifting equipment used at the mine is designed and manufactured in accordance with an appropriate standard,
MHSA Regulations, Section 8.5
The Occupational Health and Safety Act regulations relating to lifting operations are contained in the Driven Machinery Regulations:
18. Lifting machines and lifting tackle
(1) No user shall use or permit the use of a lifting machine unless -
(a) it has been designed and constructed in accordance with a generally accepted technical standard;
(b) it is conspicuously and clearly marked with the maximum mass load which it is designed to carry with safety: Provided that when this mass load varies with the conditions of use a table showing the maximum mass load with respect to every variable condition shall be posted up by the user in a conspicuous place easily visible to the operator; and
(c) it has at all times at least three full turns of rope on the drum of each winch which forms part of such a machine when such winch has been run to its lowest limit.
(2) The user shall, where practicable, provide every power-driven lifting machine with-
(a) a brake or other device capable of holding the maximum mass load should the power supply fail, or which is such that it will automatically prevent the uncontrolled downward movement of the load when the raising effort is interrupted; and
(b) a limiting device which will automatically arrest the driving effort when
(i) the hook or load attachment point of the power-driven lifting machine reaches its highest safe position; and
(ii) in the case of a winch-operated lifting machine with a lifting capacity of 5000 kg or more, the load is greater than the rated mass load of such machine.
(3) The user shall cause every chain or rope which forms an integral part of a lifting machine to have a factor of safety as prescribed by the standard to which such machine was manufactured: Provided that in the absence of such prescribed factor of safety, chains, steel-wire ropes and fibre ropes shall have a factor of safety of at least four, five and ten, respectively, with respect to the rated carrying capacity of the lifting machine.
(4) The user shall cause every hook or any other load-attaching device which forms and integral part of a lifting machine to be so designed or proportioned that accidental disconnection of the load under working conditions cannot take place
(5) The user shall cause the whole installation and all working parts of every lifting machine to be thoroughly examined and subjected to a performance test, as prescribed by the standard to which the lifting machine was manufactured, by a person who has knowledge and experience of the erection and maintenance of the type of lifting machine involved or similar machinery and who shall determine the serviceability of the structures, ropes, machinery and safety devices, before they are put into use following every time they are dismantled and re-erected, and thereafter at intervals not exceeding 12 months: Provided that in the absence of such prescribed performance test the whole installation of the lifting machine shall be tested with 110 % of the rated mass load, applied over the complete lifting range of such machine and in such a manner that every part of the installation is stressed accordingly.
(6) Notwithstanding the provisions of sub-regulation (5), the user shall cause all ropes, chains, hooks or other attaching devices, sheaves, brakes and safety devices forming an integral part of a lifting machine to be thoroughly examined by a person contemplated in sub-regulation (5) at intervals not exceeding six months.
(7) Every user of a lifting machine shall at all times keep on his premises a register in which he shall record or cause to be recorded full particulars of any performance test and examination prescribed by sub-regulation (5) and (6) and any modification or repair to the lifting machine, and shall ensure that the register is available on request for inspection by an inspector.
(8) No user of machinery shall require or permit any persons to be moved or supported by means of a lifting machine, unless such machine is fitted with a cradle approved for that purpose by an inspector.
(9) Not applicable to exploration drilling operations.
(10) No user shall use or allow the use of any lifting tackle unless the following conditions are complied with, namely that –
(a) every item of lifting tackle is well constructed of sound material, is strong enough and is free from patent defects and is in general constructed in accordance with a generally accepted technical standard;
(b) every lifting assembly consisting of different items of lifting tackle is conspicuously and clearly marked with identification particulars and the maximum mass load which it is designed to lift with safety;
(c) ropes of chains have a factor of safety with resp[ect to the maximum mas sload they are designed to lift with safety of-
(i) ten for natural fibre ropes
(ii) six for man-made fibre ropes
(iii) six for steel-wire ropes
(iv) five for steel chains; and
(v) four for high-tensile or alloy steel chains: Provided that when the load is equally shared by two or more ropes or chains the factor of safety may be calculated in accordance with the sum of the breaking strengths taking into consideration the angle of loading;
(d) wire ropes are discarded and not used again for lifting purposes if the rope shows signs of excessive wear, too many broken wires, corrosion or other defects that have made its use in any way dangerous;
(e) such lifting tackle is examined at intervals not exceeding three months by a person contemplated in sub-regulation (5) who shall enter and sign the result of each such inspection in a book kept for this purpose; and
(f) such lifting tackle is stored or protected so as to prevent damage or deterioration when not in use.
(11) The user shall ensure that every lifting machine is operated by an operator specifically trained for a particular type of lifting machine.
OHSA Driven Machinery Regulations, Section 18
It is clear that a drill rig fits the definition of “lifting equipment” or “lifting machine” and that steel-wire rope, wire rope terminations, hoist plugs, waterswivels, D-shackles, clamshells, hooks, elevators, elevator plugs and travelling blocks etc. are elements of “lifting tackle”. We have to ensure therefore that our drill rigs and all elements of lifting tackle comply with the MHSA and OHSA regulations.
It is important to recognise that the hoisting system of a drill rig is made up of many components. The mast, pullback cylinders, mast raise and dump cylinders, pulldown chains or ropes, back-stay legs and sheave wheels are all components of the lifting equipment/lifting machine and therefore they must collectively comply with the regulations.
What do these regulations mean?
The requirements in terms of the various regulations are summarised in Table 1 – comments and clarifications on some of the requirements then follow. Other important implications of these regulations will be covered in later articles.
These regulations have many implications for the drilling contractor and so in this series of articles we will examine these in some detail. Let’s look at two of the most important implications of these requirements.
Do our drill rigs comply with the legal requirements?
The requirement that drill rigs are operated at a factor of safety of 4 is very onerous – this means that if a drill rig is rated by the manufacturer to 9MT (has a pullback capacity of 9MT) then the manufacturer should be able to provide his customer with documentation to prove that the drill has a maximum capacity of at least 36 MT! I am not sure that many drills are designed and operated with this factor of safety and so I believe that many drill rigs currently operating in South Africa are potentially not legally compliant.
The documentation provided to prove the quoted pullback capacity of the drill rig can be in the form of a load test certificate or as results of a finite element analysis (FEA). These documents will be examined and approved by the appointed Manager or Engineer on the mine before the drill rig is allowed to begin operating.
It is necessary that the load test must be conducted and the results certified by a competent test facility and the FEA must be conducted by an Engineer. Simply put, this means that the drill and all ancillary parts of the hoisting system must be designed by an Engineer (or the designs must at least be authorised by an Engineer) and manufactured in a facility where standard processes are used in the manufacture of the equipment. For example, welding of any structural parts must be done by a properly qualified welder and modifications to the diesel motor must be approved by the manufacturer.
If the contractor does not have valid design specifications from the drill rig manufacturer then he will not be able to verify that the drill is being operated at a factor of safety of 4. This can happen when drill rig designs are copied or pirated and the pirating manufacturer is not able to provide the required proof of design specification. The mere fact that someone has copied another manufacturers design does not mean that the copy will have the same capacity as the original! The drilling industry is famous for pirating and contractors should ensure that their drill rig manufacturer or supplier is able to provide the required load capacity documentation before they decide to purchase.
We must bear in mind that in many projects drill rigs theoretically operate well within their design specifications and so one may assume that the factor of safety requirement can be relaxed. I do not believe that this is a good idea because drilling conditions may change which dramatically affect the load being lifted. A 9MT drill rig for example can drill HQ to approximately 790 meters but if the drill bit is blocked and the drill must pull the drillstring full of drilling fluid then the load that the drill must lift increases by 42% to 12,7MT!
Another critical consideration when determining the safe working load of a drill rig is the system of hoisting used on the drill. Hydraulic longstroke drills for example can pull drill rods either with the main pullback cylinder or with the hoist and a steel-wire rope. All manufacturers of these drills specify depth capacity by drill rod size and these depth capacities are based on pulling and lowering with the main pullback cylinder. The manufacturer does not make it clear, either in their specifications or in their sales literature that this is the case and so Contractors pull and lower to full depth using the hoist. This creates a huge problem for two reasons, the hoist is not rated to the same capacity as the pullback cylinder and the Safe Working Load of the hoist rope is nowhere near the capacity of the pullback cylinder.
A very popular drill used in Southern Africa is rated to 1520 meters in BQ and is fitted with a hoist that is rated to 8,1MT and a 16mm steel-wire rope. 1520 meters of BQ drill rod has a mass of 9MT and so the drill has a pullback capacity of 9 MT.
Many contractors will use this drill to drill 1500 meter BQ boreholes but they will pull the drillstring using the hoist! The problem is not only that the hoist is being used beyond its design limit but the steel wire rope too is being used beyond its SWL. We must remember that we have to apply a factor of safety of 6 to steel wire ropes, the best grade of 16mm rope available in South Africa will have a Proof Breaking Strength of approximately 23 MT and so a SWL of less than 4MT yet the rope is used to hoist loads of 9MT.
It is important therefore that the manufacturer provides maximum load certification for the drill rig based on the method of hoisting, we can then apply the regulated factor of safety and so determine the safe working load of the drill rig based on the method of hoisting.
What does “appropriate standard” mean?
The Acts require that lifting equipment and lifting tackle are manufactured in accordance with an “appropriate standard” or “generally accepted technical standard” but neither act defines what these terms mean. We do not have standards of manufacture of drill rigs or lifting tackle in the drilling industry and so this is an example of where we need to interpret the meaning in the context of an exploration drilling operation.
Let’s firstly consider a drill rig, every manufacturer designs and manufactures drills based on his experience and expertise and he then markets his drill based on the advantages that his drill offers (or he thinks it offers). Frequently contractors purchase drills and only once they start using the drill do they realise that the drill has limitations that were not apparent when the decision to purchase was made. I saw an example of this recently – a contractor purchased a deep hole drill but only once he started using the drill did he realise that it is only possible to rotate the drillstring anticlockwise when breaking drill rod connections. The drill rig cannot rotate anticlockwise when in drilling mode so fishing or backing off a joint downhole can only be done using wrenches.
I do not believe that the regulations are intended to regulate issues such as this – this is a feature of a drill rig that renders it more or less productive but there are a host of other features of a drill rig design that impact safety and so these should form a part of the “appropriate standard”. Let me give you some examples:
- Common sense tells us that control valves for all winches must be spring centered – this means that it is not possible to put a winch into operation and then walk away from the control but I have come across drill rigs where the wireline winch has a detented valve.
- Drill rigs must have more than one an emergency stop (E stop) but most manufacturers provide only one situated at the Driller control panel.
- Controls for set-up of the drill rig must be able to be isolated so that they cannot be activated when the drill is in drilling mode but on many drill rigs this is not the case.
I believe that these requirements (and many more) collectively should form the “appropriate standard”.
In future articles we will discuss many other legal requirements that impact the drill rig manufacturer and the design of drill rigs and so one of the objectives of this series of articles is the development of a safety standard that can be applied to exploration drill rigs.
Before we leave this issue we need to also look at lifting tackle. The factor of safety of 4 and the “appropriate standard” requirements apply also to the manufacture of lifting tackle and so manufacturers must be able to provide proof of the safe working load claims of their equipment and the equipment must be clearly and conspicuously marked with it’s Safe Working Load.
This would typically be done by testing a number of samples to destruction, an average load at failure can then be determined, the required factor of safety applied and the safe working load determined, the equipment can then be marked with the Safe Working Load.
It is obviously critical that all similar pieces of equipment manufactured by the manufacturer are identical and so the equipment must be manufactured in a standard way, using the same materials and processes as the pieces that were tested and certified. In other words, the manufacturer must be able to show that he manufactures to an “appropriate technical standard”.
In a drilling context this is not as easy as I have made it sound – consider a hoist plug for example, a typical hoist plug will consist of 4 parts, the hoist plug eye, the hoist plug body, the spindle and the bearings and lock nut that holds the spindle in place. Which piece of the hoist plug should be marked? Should all of the parts be marked?
The problem is compounded when a contractor changes a part of a hoist plug – he may change the spindle for example and so the certified safe working load of the “new” assembly may then be compromised. I do not know what the answer is but I do know that we have to comply with the law and so I suggest that the risk of compromising the safe working load of a piece of lifting tackle can be managed quite simply by instituting a procedure to ensure that lifting tackle is not repaired but is discarded when it is worn or when it reaches a fixed service life. Alternatively, a procedure can be instituted to ensure that any parts replaced are OEM manufactured and are replaced according to a procedure provided by the OEM. You may say that this is crazy - it is easy to strip and reassemble a hoist plug, what about a waterswivel or a safety overshot. These are not so easy and so it is important that contractors insist on the OEM producing the necessary certification and procedures to allow the contractor to comply with his legal obligations.
In next month's technical series, I will examine in detail some more of the requirements for hoisting operations and delve a bit more deeply into practical management of the risks associated with hoisting operations. Please make sure you have subscribed to DrillSafe in order to receive the latest issue.