MINING MACHINES ELEMENTS PACKING AND SECURING ON PLATFORM CONTAINER Summary

The scientific purpose of this paper was to analyse the problem related to intermodal transportation of mining components packed in containers or other cargo transport units coupled with the problem of its proper securing. In this article, the issue of exposing the load to the effects of inertia forces which might cause unintentional movement is presented. The methods of securing the heavy load in cargo transport units are reviewed in the context of cargo immobilisation possibilities while reducing the load sensitivity to mechanical forces. The research part of this article presents the methods of packing and securing an atypical load, which is a part of a mining machine weighing 18t. This paper presents the results of calculations of inertia forces acting on the transported cargo, packed on a container platform. Based on the results, the cross fixing method was selected to secure the cargo and further decisions were made on the type and quantity of conveyor lashings necessary for the safe and correct carriage of the atypical load.


INTRODUCTION
Road transport vehicles are characterised by widespread availability, flexibility and speed. Due to the very large diversity of goods and means of transport used, the method of attachment must be adapted to the needs every time to maintain maximum safety for both the traffic load, vehicle and other road users. However, the results of vehicle inspections show that some of the loads carried are not properly secured on road vehicles. It is estimated that about 25% of accidents involving trucks result from improper cargo protection [2,20].
The issue of freight transport security deserves special attention due to the huge, negative consequences that entail, for example, losing a heavy load during an emergency and uncontrolled situation. It is important to determine the impact of unsecured or incorrectly secured load packages in any transport unit on the effects in the form of collisions and accidents. More so, it is worth realising that responsibility for errors arising from unsecured loads, which, according to the European and global law, concerns all participants in the transport chain. Shippers, who usually pack goods for shipments are similarly responsible for the loads' safety in their supply chains [1,2,13,19]. Human error [2-4, 6, 14, 21] and the problem of causality [7] in the analysis of accidents are widely investigated, providing enrichment of knowledge about methods, procedures and tools allowing incident and accident prevention or prediction [8].
The knowledge of cargo and packing dynamics has improved over the years [10]. Although there are many methods and tools supporting cargo security [5,22], during road transportation, packed cargo is exposed to other independent random factors. One is the impact of inertia forces that can cause movement of packaged goods. The direction of these forces depends on changes in the speed vector of the vehicle, and in particular, in the direction of the vehicle during braking, towards the rear of the vehicle during the start-up, or facing transversely to the vehicle when the transport vehicle is travelling on a curvilinear arc. In each of the specified cases, the vector of inertia forces takes the direction of the acceleration vector and its value is proportional to the value of the vector resulting from the velocity. In addition, the load can be influenced by the forces resulting from the movement of the vehicle on the road with its significant inclination and uneven ground. However, there are some studies focused on non-lashing cargo securing methods [9,11,24].
Load sensitivities for mechanical effects can be reduced by appropriate immobilisation, that is, by employing suitable fastening elements. These fastening elements include fastening belts, chain hoists, rope hoists, locking elements, etc.
By selecting appropriate methods and tools for securing specific loads, it should be emphasised, that improper attachment of the load could result in a dangerous road situation; often resulting in loss of life or health of its participants.
Currently, legal acts are regulating the requirements for proper protection of loads during their transportation. Within the European Union, the legal issue of cargo carriage is regulated by EN-12195. In many countries, this standard has been obligatory for many years, but still not fully respected by the road hauliers community. However, it is known that the responsibility for properly securing the transported cargo lies directly on the carrier. Surprisingly, the fact remains that dangerous road events still occur, which can be traced to erroneously secured loads, the reason being lack of knowledge of the problem. These errors often arise at the loading stage and are often identified for non-typical loads. Load conditions are extremely important for assessing the carrier's reliability [12,15,23].

7.
This article presents a practical example of correct safeguarding of an atypical, 18t load based on the calculated inertia forces acting on the transported cargo that is placed on the container platform. Securing the load was done with the cross fixing method.

NECESSITY OF CARGO IMMOBILISATION
Transportation of machines or other devices, which are usually oversized or extremely expensive, consists of complex actions involving the movement of cargo and handling operations (loading, unloading and reloading). Such transportation requires specialised knowledge and equipment and every part of the process should be carefully planned [15]. Fig. 1 presents the essential elements of significant transportation process planning. All elements indicated, affect the quality of the transported goods and the quality of transport service. When planning both recurring and single shipments, a proper loading unit must be selected and adapted to the type of load and the mode of transport. The appropriate choice of means of transport (loading unit) for the shipment is influenced by several factors, such as mode of transport, type of package, delivery time, density and quantity of the product, requirements for previous loads, additional equipment, load and securing type or vulnerability to the external transport conditions. Some of them refer to the conditions of transporting goods, and others to the packages or transport units used or even to the requirements for equipment and supplies [16].
Requirements for equipment, supplies, and loading/unloading technique should be confirmed with the carrier to maximise optimisation [12]. This information will help the carrier easily organise the transportation of specific goods. For some products, the package or transport unit used must be specially designed to maintain safety in the transport process. Ensuring safe transport depends on many factors, including the correct selection of packaging or transport unit and fixing means [17]. The decision, however, depends on the forces acting on the load.

Proper load securing
Securing of loads during transport is reduced to balance the inertial forces acting on the load when the vehicle is moving during acceleration, braking, cornering or overtaking manoeuvres, etc. The frictional forces that occur between the surface of the cargo floor of the vehicle and the lower surface of the load are often insufficient to ensure that the load does not move. Vertical movements of the load during driving due to bumps and vibrations reduce the frictional force resulting from contact. For fixing packages or loads on vehicles, elastic belts, ropes or chains, equipped with mechanical tensioning devices (latches, clamps, stabilisers tensioners) are used. The carrier responsible for securing the cargo before transport selects the appropriate number of fixing lashings by him or herself, considering the mass of the transported load and its external dimensions, which affects the choice of type and strength parameters of the fastening elements as the basis of the decision. These principles refer to different types of cargoes, except liquid cargoes and gas. The most common cargoes, their stowage and calculation are container cargoes, reefer cargoes, bulk cargoes including grain and grain products, heavy lift cargoes, timber cargoes, steel cargoes and ro-ro cargoes [18].
The appropriate computational analysis is required to determine the forces transmitted by the load securing elements. This analysis must consider the following three basic situations that are usually encountered during road transport: − braking of the vehicle while driving straight ahead, − braking on the curve of the road when the load on the vehicle is inertia, both in the driving direction and in the lateral direction outside the arc, − intensive braking of the vehicle when driving straight ahead on uneven surfaces, − vibration of the vehicle causing reduction of the load pressing the load to the floor of the cargo hold, thus reducing the friction between the cargo and the cargo area.
These problems refer not only to the cargo packed inside transport units but also to the transport units themselves (egg containers) that have to be properly secured [19].

Forces acting on packed cargo in transport
The maximum acceleration acting on the load while driving is determined by the acceleration product g and the acceleration factor C as defined in the standards [3,19]. Acceleration factors are regulated by European standards and the IMO, and differences in values are detailed in Table 1. In addition to the guidelines contained in the IMO, the United Nations Economic Commission for Europe recommends using the EN 12195-1 standard in which it has drawn up the European Commission guidelines on cargo security, and the differences between those provisions are shown in Fig. 2. Many experts from the European Commission and scientists worked to elaborate parameters acceptable to obtain the European standard [1,3,19]. showing how a particular type of transported cargo should be properly secured, for example, metal circles, large panes of glass, steel pipes, etc.
Road Transport Inspection and similar institutions checks are very accurate at the security control of cargo, which greatly contributes to the improvement of safety in international transport since the vehicle with improperly secured load is stopped in the parking lot and cannot set out on a further route until it is rectified. This is related to vehicle downtime and the need to supply the driver with appropriate fastening means.

Load characteristics
The case study in view is based on an order received by a multimodal transport operator from a global mining machinery and equipment manufacturer specialising in underground mining, open-pit mining, and bulk cargo transport and handling. The subject of the order was the transport from Poland to Jakarta Port in Indonesia of five coal conveyors to carry coal in the open-pit mines. The whole project was divided into four stages, including multimodal transport. The transported machines were divided into 122 separate load units due to their size. Transport took place on standard semi-trailers: tarpaulin of dimensions: width: 2.48 m, height: 2.70 m, length of 13.6 m and container and cargo units 40 feet plate-type Flat Rack Containers or multi-purpose containers.
The untypical load analysed in detail in this article is the opencast mine belt conveyor system of which loading by a reach stacker is shown in Fig. 3. The mass of the load is mL=18 000 kg, width d=3.2 m, height h=3.0 m and length l=9.5 m.

Forces acting on the transported cargo
In the longitudinal direction, the Fax inertia force acts on the load that occurs during the braking FaxH and the acceleration FaxR of the vehicle. While driving along the curvilinear path, centrifugal force Foz is created, because the uneven surface of the road is a source of inertial force Fby acting vertically. The values of the forces of inertia are calculated as the product of the acceleration of gravity C and derived from the load being transported QL according to the formula: The values of Cxyz acceleration factors are normalised for the different directions of inertial forces and the values were shown in Table 1 according to the European standard.

Calculation and selection of lashings for conveyor attachment on a container platform
The cargo on the container platform of the vehicle should be protected against slipping while driving, to ensure the safety of the driver, the traffic and to secure the load from possible damage. Different methods of fixing cargo on means of transport are used in transport. The basic ones are: blocking, anchoring using lashing, increasing the value of friction force of the load on the floor of the body by the belt lashing method. In practice, combinations of these methods are usually used. The purpose of this combination is to improve the efficiency of the loaded cargo. For the mounting of the conveyor belt drive system, the cross anchoring method with belt lashing was used. The cross anchoring method allows attaching a heavyweight load using only four lashings that secure the load from moving in both the transverse and the longitudinal directions. However, a necessary condition for using this kind of protection is that the load has special handles to fix the lashings used.
The selection of cross anchoring lashing is to determine the minimum value of the LC lashing capacity for each of the lashes located at the front (LPp) and the back (LCt) of the container platform. To determine the lashing capacity, it is necessary to analyse the inertia forces of the transported load at the time of the most unfavourable conditions (like roadblock overcoming) occurring in road transport. During breaking, the inertia force Faxh, is determined by the following relation (2) (Fig. 6) and is calculated as follows: where: ax -accelerated deceleration at braking, mL -load mass.
Therefore, while braking the Faxh inertia force acts on the load with 141 264 N. At the moment of braking, the load is secured with 1, 1', and 3, 3' lashings. In addition to FaxH inertial force also opposes the FT frictional force between the surface of the platform container and the wooden sleepers under load. The friction force FT (3) is directed opposite to the force causing the load shifting according to the relation (Fig. 7). 13.
For wooden beams and metal substrates, the coefficient of friction is in the range µ=0.2-0.5. The most unfavourable value was considered, that is, µ=0.2. In the case of cargo resting horizontally on the platform, the load force N and the gravity of the load G are equal (N=G). Apart from these forces, in this case, the load was additionally compressed by the 5 and 5' belt tension. Then on the force of pressure N, in addition to the gravity G, there is also the pressing force Pn, derived from the tension of the belts 5 and 5'. Thus, the load pressure on the substrate, including the fixing straps, is: where: Pn -additional force pressing the load to the cargo platform of the container.
Belt tensioners increase the clamping force by an additional value of Pn = 5000 N (standard tension force STF). After substituting the appropriate size and calculating the frictional force, FT has the following value: The frictional force, after considering the forces from the load and the pressing straps, is FT=36 316 N. At the moment of braking, after taking into account the force of friction of the load and the pressing of the belts, the final inertial force FaxH is applied to the transported load with the following values according to the following relation: The resulting value (6) is inertial force FaxH that acts directly on the load at the time of braking and to which should be secured with lashing equipment no. 3, 3' and 1, 1'. After determining the magnitude of the inertia force acting on the load at the moment of deceleration, the centrifugal force Foz acting on the load at the moment of travel on the curve is determined according to the relation (Fig. 8): where: mL -load mass, v -speed of the vehicle with the load, R -radius of the road arc.  (7), the centrifugal force at the level Foz=35 520 N is obtained. On the other hand, considering the European standard and other adverse road conditions related to sudden lane change such as avoiding an obstacle, the centrifugal force is: Taking into account the frictional force of FT, the final centrifugal force Foz acting on the considered load is: The determined values of forces acting on the conveyor drive system on a container platform are presented in Table 2.
Tab. 2 Values of forces acting on a conveyor drive system packed on a container platform Direction of force Force value In the direction of the longitudinal movement, at the moment of braking F axh = 141 264 N In the direction of the opposite longitudinal movement at the moment of starting F oz = 53 684 N In the transverse direction when driving on the arc of the road Vertical direction when driving on uneven roads F by = 90 000 N Sensors of vectors of the reaction forces in lashings no. 1, 1', 2, 2', 3, 3', 4 and 4' are opposed to the return forces during transport loads on the platform of the container. The inertia force Foz is directed forward and its effect is transferred to the cross-lashings no. 4, 4' and longitudinal lashings no. 2, 2'. Foz centrifugal force acts transversely to the direction of travel, and its operation is transferred to the cross lashings no. 3 and 4. When Foz centrifugal force changes, the reactions will occur in 3' and 4' lashings. Tilt angles of lashings are required to determine the reaction forces. Fig. 9 shows the angles β1, β2, describing the arrangement of cargo lashing in the Oxz plane at reaction point C. Fig. 9. Angles of lashing no. 3 alignment at the C3' attachment point Reactions considered at points C and C' are the condition of the load when the transported load on the container platform is affected by the forward inertia force FaxH as a result of the vehicle braking. The reactions at points C and C' have the same values (S3x=S3'x) since the fixing lashing are arranged symmetrically. Strength S3 was decomposed into components acting in directions Ox, Oz.
Similarly, the S1 force in the direction of Ox and Oz was decomposed into the force of the reaction of lashings 1 and 2 at points C1 and C2. S 1x = S 1 • cosα 1 (12) S 1y = S 1 • sinα 1 The S3x, S3x' and S1x, S1x' reaction forces maintain the charge in equilibrium when the inertial force at the moment of braking FaxH is acting in the longitudinal direction. The load remains in balance if: When S1=S1', S3=S3', then the equation takes the following form: After substituting the relations defined in equation (10) and (12) into equation (15), we obtain: 2(S 3 • cosβ 3 • cosβ 3x ) + 2(S 1 • cosα 1 ) ≥ F axH (16) Equation (16) presents the state of equilibrium at the moment the vehicle brakes. To determine the forces in the S3 and S1 lashings, tensile forces in lashings 3 and 4 arising from the centrifugal force at the moment of the arc or other lane change manoeuvre must be determined.
When driving on the arc of the road, lashings 3 and 4 are tensed under the influence of the centrifugal force Foz, based on the dependence: After substituting dependence (11) and assuming that S3z=S4z due to the symmetry of the attached load, the equation (17) takes the following form: After transforming the equation (18) to S3, we obtain the equation of the force in fixing lashing 3 and simultaneously in lashing 4.
It is clear from the calculation that the fixing lashings 3 and 4 have a tensile strength of 52,083.3 N. It follows that the forces acting on the lashings of cross attachment S3,3'=52 083.3 N. If the load acting on the 3 and 4 lashings is known, the force that tenses the 1 and 1' lashings can be determined. Due to the symmetry, only S1 may be calculated. After substituting the force S3 for the equation and the corresponding transformation, we obtain the force S1,1'=20 290.85 N.
The analysis shows that for the conveyor drive system transported on the container in the individual attachment lashings force values appear as presented in Table 3.
Following the analysis, associated with the forces, selection of appropriate fixing equipment should be done according to lashing capacity (LC).

Selection of lashings securing transported cargo
To secure the conveyor on a container, according to the guidelines contained in the standard, the following fixing lashings should be applied: S1, S1' and S2, S2', lashings should have a tensile strength of S1,2 =20 291 N, lashings S3, S3' and S4, S4' should have a tensile strength of S3,4=52 083 N and lashing S5=22 500 N.
Lashing straps recommended by the carrier was selected for conveyor attachment. Lashing straps usually consist of artificial fibres (usually polyester according to EN 12195-2). Each tape harness is labelled with the appropriate information, shown in Fig. 10, which is lashing capacity (LC) in decaNewtons (daN-official force unit corresponding to 1 kg), standard tension force (STF) which is obtained when the manual force is applied to the tensioner (SHF) [3,19]. Fixing equipment in the form of fastening belts should be made following the EN 12195-2 standard. Companies that manufacture these types of fastening belts have the straps in their assortments in the following ranges: − lashing strap width from 25 to 75 mm, − lashing strap maximum load from 250 to 10 000 daN, − safety factor of the securing straps is 2.
When attaching an 18t load on conveyor drive system, the following fastening belts should be used [12]: a. for lashings: S1, S1' and S2, S2' one-piece belt with manual tensioner was used (Fig. 11) Fig. 11. Fastening strap used for lashings S1, S1' and S2, S2' This type of lashing strap has the following parameters and implementations used ( Two-piece with profile hooks Two-piece with U-type hooks Two-piece with carabiners hooks One-piece with a closed circuit b. for lashings: S3, S3' and S4, S4', the following fastening straps were used (Fig. 12): This type of lashing strap has the following parameters and implementations used ( Two-piece with profile hooks Two-piece with U-type hooks Two-piece with carabiners hooks One-piece with a closed circuit For load safety, the use of a similar procedure for choosing the form of security and fixing means selection is recommended, analysing each case separately at the planning stage of the transport process according to standardisation [1,3,19].

CONCLUSIONS
This article is focused on intermodal transportation of mining components packed in containers or other cargo transport units together with the problem of its proper securing. Using appropriate equipment, method of cargo securing and correct transport unit are very important elements among the six key factors mentioned as most important of proper and safe transportation planning. The decision of packaging and fixing means selection, however, depends on the forces acting on the load. EN 12195-1 standard is usually used for calculation of securing forces which contains the European Commission guidelines on cargo security. However, many carriers use the VDI2700 German standard where the basic forces acting on the cargo, practical way of proper location and installing the fastening devices are explained. Furthermore, this article presents a case study of container packing and securing of a mining conveyor, which was sent from Poland to Indonesia. First, the strap cross fixing method was determined with five lashings. Thereafter, considering the friction forces of the load and the lashing pressing forces, final inertial force (FaxH=104 948 N) while vehicle braking was calculated. It should be secured with lashing equipment no. 3, 3' and 1, 1'. While driving on a curve road, centrifugal force (Foz=53 684 N) influences the 3' and 4' lashing rods. Then, forces acting on the lashings of cross attachment S3,3'=52 083.3 N were determined and are the same for lashings 4 and 4'. Basing on this knowledge, lashing strap of 75 mm width and lashing capacity LC=5 000 daN was selected for cargo securing. Similarly, forces acting on lashings 1, 1' and 2, 2' were determined (S1,1'=20 291 N) and appropriate strap of 50 mm width and 2 000 daN lashing capacity was proposed. For lashings 5 and 5' (S5,5'=22 500 N), strap with 50 mm width and LC=2 500 daN lashing capacity is proposed. Finally, various types of usable selected belts with different hook variants were presented.