1 ACCESS POINTS Field of the Invention The present invention relates to a cover, such as a tarpaulin, for covering a pile (e.g. a pile, stockpile or haystack). Background The words "pile", "dump", "stockpile" or "haystack" and all other appropriate terms will be used interchangeably hereafter, though the word "pile" is intended to encompass within its scope the scope of the other terms. A cover, which will hereinafter be interchangeably referred to as a tarpaulin, is commonly used to cover and protect a dump from weather or contaminants. A cover can also assist in digestion and decomposition of material in the dump (e.g. a silage bin). A cover or tarpaulin is, in essence, a large sheet or a plurality of sheets connected by sewing or welding, that overlays a dump to provide a physical barrier to direct impact of weather or contaminants on at least a portion of the dump. Tarpaulins are typically light-weight and, due to their large surface area, are readily blown off the dump or stockpile. Tarpaulins have traditionally been weighed down to prevent them from blowing off dumps. However, the tarpaulin can still billow when a breeze blows under its edges or across the tarpaulin and thus the weights (e.g. tyres), which tend not to be uniformly distributed over the cover, cause a non-uniform stress distribution across the tarpaulin, increasing wear and decreasing the working life of the tarpaulin. Such a breeze can also result in the tarpaulin tearing and/or dislodgement of the weights and the tarpaulin can therefore blow away. To ensure tarpaulins are securely held in place regardless of breezes, they have more recently been secured in place by clips, cinches, pegs, sandbags or soil fixed along their edges. Such securing mechanisms still allow breezes to affect the tarpaulin and as the tarpaulin billows stress is placed on the points at which the securing means are connected to the edges of the tarpaulin and cause flex wear to the body of the tarpaulin. The increased stress ultimately results in premature wearing of the tarpaulin. Tarpaulins for fitting over large dumps are typically stored in a folded, concertina fashion. When being positioned over a dump, such tarpaulins are 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 2 pulled from opposite corners of the tarpaulin along either side of the dump to cover the dump. Given the weight of a large tarpaulin, and the height of dumps over which large tarpaulins must be dragged, a significant amount of force is required to drag a large tarpaulin over a dump. In order to impart the force on the tarpaulin it is common to bunch up in the corner of the tarpaulin, tie it to a vehicle using a rope or strap as an intermediary, and use the vehicle to tow or pull the tarpaulin over the dump. Using vehicles to tow tarpaulins over dumps often results in the corners of tarpaulins becoming torn and damaged. Summary Disclosed herein is a cover for covering a large pile of material such as grain, comprising: a sheet to overlay the large pile of material, wherein the sheet comprises a plurality of sub-sheets attached together and wherein at least a part of the sheet contacts the pile of material; a small opening in the part of the sheet that contacts the pile of material such as grain through which the material is accessible for sampling; and a resealable access point attached to the sheet about the small opening, the access point comprising an elongate zip attached to the sheet and moveable between an open condition in which the pile can be accessed, and a closed condition for preventing access to the pile; wherein the zip has a length that extends in the elongate direction across only a part of the cover; and wherein the small opening includes a flexible sleeve in register with the small opening so that, when in use, the pile can be accessed through both the sleeve and small opening together. Disclosed herein in a cover for covering a large pile of material such as grain, comprising: a sheet to overlay the large pile of material, wherein the sheet comprises a plurality of sub-sheets attached together and wherein at least a part of the sheet contacts the pile of material; a small opening in the part of the sheet that contacts the pile of material, such as grain, through which the material is accessible for sampling; and 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 3 a resealable access point attached to the sheet about the small opening, the access point comprising an elongate zip attached to the sheet and moveable between an open condition in which the pile can be accessed, and a closed condition for preventing access to the pile; wherein the zip has a length that extends in the elongate direction across only a part of the cover; and wherein in the open condition the access point permits access by a sampling device to the underlying material such as grain, but is too small to allow passage of a person from one side of the cover to the other. Disclosed herein is a cover for covering a pile, comprising: a sheet to overlay the pile and comprising an opening through which the pile is accessible; and a resealable access point attached to the sheet about the opening, the access point comprising an access member attached to the sheet and moveable between an open condition in which the pile can be accessed, and a closed condition for preventing access to the pile. The access member comprises a zip. The opening may comprise a flexible sleeve in register with the opening so that, when in use, the pile can be accessed through both the sleeve and opening together. The cover may comprise a plurality of resealable access points. Disclosed herein is a cover for covering a pile, comprising: a sheet to overlay the pile; and at least one restraint attached to the sheet, a free portion of each restraint extending from the sheet to be fixed in relation to the pile in use, thereby to fix the sheet in relation to the pile, and a sheet contacting portion of each restraint extending at least partially over the pile in use. The cover may comprise a plurality of restraints. At least one restraint may have two free portions extending from the sheet at respectively different positions to be fixed in relation to the pile. The sheet contacting portion may be received in a sleeve attached to the tarpaulin, the or each free portion extending from the sheet contacting portion. The or each free portion may be provided with a stop for preventing the end of the restraint from withdrawing or retracting the sleeve into the sleeve. Disclosed herein is a cover for covering a pile, comprising: 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 4 a sheet to overlay the pile and comprising an opening through which the pile is accessible; and a resealable access point attached to the sheet about the opening, the access point comprising an access member attached to the sheet and moveable between an open condition in which the pile can be accessed, and a closed condition for preventing access to the pile. Disclosed herein is a cover for covering a pile, comprising: a sheet to overlay the pile; and an anchor system attached to an outer surface of the sheet, to which an operator can releaseably attach to maintain the operator on the pile when in use. Disclosed herein is a cover for covering a pile, comprising: a sheet to overlay the pile; and a plurality of restraints attached to the sheet, a free portion of each restraint extending from the sheet to be fixed in relation to the pile in use, thereby to fix the sheet in relation to the pile, and a sheet contacting portion of each restraint extending at least partially over the pile in use. The cover may be used for covering a pile. The cover may overlay the pile to protect the pile from weather. The cover may overlay the pile to protect the pile from pests. The cover may be used for covering a dump. The cover may be used for covering a stockpile. The cover may be used for covering a haystack. The cover may have any desired shape. The cover may be substantially rectangular. The cover may be fabricated from any appropriate material. The cover may be formed from a polymeric material. The cover may comprise a polymeric sheet. The cover may be fibre reinforced. The cover may comprise a tarpaulin such as, but not limited to, a sheet or body. The tarpaulin may be formed from one or more separate sheets of material. When the tarpaulin is formed from two or more sheets attached together to form a tarpaulin, those sheets may constitute subsheets. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 5 Each subsheet may constitute less than the entirety of the body of the tarpaulin. The subsheets may be connected together along connection lines. Each subsheet may be 2m wide. The subsheets may not have the same size. The subsheets may not have the same shape. The tarpaulin may comprise end subsheets. The outer ends of the end subsheets may be tapered or folded. The cover may comprise one or more restraints. The cover may comprise a plurality of restraints. The or each restraints may be attached to the tarpaulin. Restraints may be attached to both sides of the tarpaulin. The or each restraints may be attached to the tarpaulin at regular intervals. The regular intervals may be regular intervals along the length of the tarpaulin. The or each restraint may be formed from any appropriate material. The or each restraint may comprise a strap. The strap may be formed from webbing. The or each restraint may include a free portion. The free portion may comprise part of the strap. The free portion of each restraint may extend from the tarpaulin. The free portion of each restraint may extend past an edge of the tarpaulin. The or each restraint may be fixable in relation to the pile when the cover is in use. Fixing the or each restraint in relation to the pile may fix the tarpaulin in relation to the pile. The or each restraint may include a sheet contacting portion. The sheet contacting portion may comprise part of the strap. The sheet contacting portion may extend at least partially over the pile when the cover is in use. The or each sheet contacting portion may extend into a sleeve. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 6 The sheet contacting portion of one or more of the restraints may extend over the pile from at or near one side of the sheet to at or near an opposite side of the sheet. The sheet contacting portion may be fixed to the tarpaulin. The sheet contacting portion may be movable with respect to the tarpaulin. The sheet contacting portion may slide with respect to the tarpaulin. The restraints may apply down force to the tarpaulin. The down force may be applied at the point where the or each restraint is connected to the tarpaulin. The down force may be applied at the position where the or each restraint is connected to the tarpaulin. The down force may be applied at the region where the or each restraint is connected to the tarpaulin. The down force may be applied to the or each restraint by wind loading. The or each restraint may distribute load over a portion of the tarpaulin. The or each restraint may be loosened to adjust the load applied to the tarpaulin. The or each restraint may be tightened to adjust the load applied to the tarpaulin. Where a plurality of restraints is provided, the restraints may be separately loosened. Where a plurality of restraints is provided, the restraints may be separately tightened. The or each restraint may be positioned generally centrally on each subsheet. The or each restraint may be positioned generally centrally on the tarpaulin. The or each restraint may be positioned on either side of joins between subsheets. The or each restraint may be equidistantly spaced away from the join on either side of the join. The or each restraint may extend along the join. The or each restraint may extend along the join on top of the subsheets. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 7 The or each restraint may extend substantially perpendicular to a join between subsheets. The or each restraint may extend from one side of the tarpaulin to the other. The restraints may extend diagonally along the tarpaulin. The direction of extension of each restraint may be substantially linear. Where the end subsheets are tapered or folded, the restraints extending through the tapered or folded portions may be shortened. The length of the or each restraint may be changeable to suit the shape of the cover. The length of the or each restraint may be changeable to suit the shape of a subsheet. The length of the or each restraint may be changeable to suit the configuration of a subsheet. At least one restraint may have two free portions extending from the sheet at respectively different positions to be fixed in relation to the pile. The restraint may comprise a strap with the two free portions comprising parts of the same strap. The two free portions may extend from the tarpaulin at respectively different positions to be fixed in relation to the dump. The sheet contacting portion of the respective restraint may be positioned between the two free portions. The two free portions may extend away from opposite edges of the tarpaulin. The sheet contacting portion of the or each restraint may extend over the dump from at or near one side of the tarpaulin to at or near an opposite side of the tarpaulin. The sheet contacting portion may apply a uniform load across the width of the tarpaulin. The or each restraint system may include a restraint containment member for containing a portion of the restraint. The restraint containment member may comprise a sleeve. The sleeve may be fixed to the tarpaulin. The sheet contacting portion of the restraint may be received within the sleeve. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 8 The sheet contacting portion may slide within the sleeve. Sliding of the sheet contacting portion of the restraint may adjust the length of the free portion(s) of the restraint. The sleeve may have an opening that delineates the end of the free portion and the commencement of the sheet contacting portion. The opening may be reinforced. The opening may be reinforced by attaching material around the opening. The opening may be reinforced by sewing or welding webbing material around the opening. The opening may be reinforced by anchoring a metal ring to the end of the sleeve at the opening. The opening may be reinforced by anchoring a metal ring to the end of the sheet contacting portion at the opening. The sleeve may be open at both ends. Each of two free portions of a restraint may extend from respective ones of the open ends of the sleeve. The free portions may extend from opposite edges of the tarpaulin. The sleeve may be attached to the tarpaulin by any appropriate means. The sleeve may be attached to the tarpaulin by welding or stitching. The sleeve may extend between opposite edges of the cover. The sleeve may be formed at a join between subsheets. Two subsheets may be joined along two parallel joining lines, the sleeve being defined by both subsheets and the joining lines. The or each sleeve may comprise a fixed portion fixed in position relative to the tarpaulin. The sleeve may comprise a flexible portion. The flexible portion may extend from the fixed portion. The flexible portion may extend to the free portion of the restraint. The flexible portion may move with the free portion towards and away from the fixed portion. The flexible portion may prevent access of pests and contaminants into the sleeve. The flexible portion may be able to be pulled so as to evacuate the sleeve. The flexible portion may be sleeve-shaped. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 9 The flexible portion may comprise an elasticised patch having an opening therein through which the strap of the restraint passes, the slit contacting both sides of the strap during movement of the strap. The fixed and flexible portions may comprise a single unitary body that is partially attached, at the fixed portion, relative to the tarpaulin. The free portion of the or each restraint may be provided with a stop for preventing the end of the restraint from withdrawing or retracting the sleeve into the sleeve. The stop may comprise a piece of rubber attached at an end of the free portion. The piece of rubber may be stitched to webbing of the restraint. The stop may be too wide to retract into the sleeve. The free portion(s) of the or each restraint may be fixed in relation to the dump by any known means. The free portion(s) of the or each restraint may be fixed in relation to the dump by pegs wedged into the ground. The free portion(s) of the or each restraint may be fixed in relation to the dump by a ratchet system. The free portion(s) may form one part of a ratchet system. The cooperating part of the ratchet system may be fixed to a base under the dump. The ratchet may enable the progressive tightening of the or each restraint onto the dump. Tightening of the or each restraint onto the dump may involve drawing more of the free portion of the respective restraint into the ratchet. The ratchet may enable the progressive loosening of the or each restraint. Loosening of the or each restraint may involve releasing more of the free portion of the respective restraint from the ratchet. The ratchet may enable the controlled loosening of the cover. The free portions may be anchored at different distances from the tarpaulin. The restraints may comprise a strip extending at least part way over the dump and stitched or welded to the tarpaulin. The restraint(s) may comprise webbing material. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 10 The restraint(s) may comprise a weldable PVC webbing welded directly to the tarpaulin. The restraint may be stitched or welded to the tarpaulin along the length of the strip. The restraint may be stitched or welded to the tarpaulin at the end of the respective strip remote from the end secured in relation to the dump. One or more restraints may be attaches to one or other side of the cover. One or more restraints may be attached to both sides of the cover. Disclosed herein is a method for adding material to a pile comprising: providing a cover including a tarpaulin and a plurality of restraints, the cover at least partially covering the pile; loosening at least a first one of the restraints; forming a fold in the tarpaulin to fold the tarpaulin back over itself, and locating the fold at a second one of the restraints, to expose part of the pile; and tightening the second one of the restraints to secure the tarpaulin at the fold. In a first configuration a first side of the tarpaulin will face upwardly and a first restraint positioned on the first side will be accessible and securable to maintain the tarpaulin in position over the pile. In a second configuration a second side of the tarpaulin will face upwardly and a second restraint positioned on the second side will be accessible and securable to maintain the tarpaulin in position over the pile. The or each restraint may be waterproof. The sleeve may be waterproof. There may be provided a kit for forming a restraint for a cover. The kit may comprise a restraint and restraint containment member for containing a portion of the restraint. The kit may comprise a plurality of restraints and restraint containment members. Each restraint containment member may comprise a fixed portion for fixing to a cover. Each restraint containment member may comprise a flexible portion attached or attachable to one or both of the fixed portion and respective restraint. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 11 One end of the restraint may be attached to the restraint containment member. The other end of the restraint may be attachable to the restraint containment member after cutting of the restraint to size. For the avoidance of doubt, the term 'restraint' may be replaced with restraint system' as required in the context. The cover comprises an opening through which the pile is accessible. The cover may comprise a slit through which the pile is accessible. The cover includes an access point or vent. The cover may include a plurality of access points or vents. An access point or vent may be on the tarpaulin. An access point may be positioned anywhere on the tarpaulin. An access point may be attached to the tarpaulin about the opening. An access point or vent may permit access to the pile beneath the cover. An access point or vent may be resealable. An access point or vent may not be resealable. An access point may be located on the tarpaulin in a position that will be at the top of the pile when the tarpaulin is on the pile. An access point may comprise a flexible member attached to the tarpaulin. An access point may comprise an access member attached to the tarpaulin. The flexible member may comprise a sleeve. The flexible member may be movable between an open condition and a closed position. The access member may comprise a sleeve. The access member may be movable between an open condition and a closed position. In the open condition the dump may be accessible. In the open condition the dump may be accessible through the access point. In the closed condition access to the dump through the access point may be prevented. The flexible member may be in register or alignment with the opening. The access member may be in register or alignment with the opening. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 12 The access point may be adapted to receive an implement through the flexible member and opening. The access point may be adapted to receive an implement through the access member and opening. The implement may be a grain sampler. The sleeve may be a flexible tube. The sleeve may be fixed to a fabric patch that is fixed to the tarpaulin. The fabric patch may be substantially square. The join between the sleeve and patch may be reinforced. The sleeve may be fixed directly to the tarpaulin. The access point may be retrospectively fitted to an existing tarpaulin. The flexible member may be at least partially flattened when in the closed condition. The access member may be at least partially flattened when in the closed condition. The sleeve may be at least partially flattened when in the closed condition. The flexible tube may be at least partially flattened when in the closed condition. Flattening may shut the flexible member, sleeve or tube as the case may be. The sleeve may be flexible, yet heavy, so that it will tend towards laying flat against the tarpaulin. The sleeve may be flexible, yet heavy, so that it will tend towards laying flat against the patch. The access point may be maintained in the closed condition by a closing member. The access point may be maintained in the closed condition by a clamp. The access point may be maintained in the closed condition by a closing member. The access point may zip to the tarpaulin. The access point may zip to a patch on the tarpaulin. The access point may zip closed. The sleeve may be maintained in the closed condition by a closing member. The sleeve may be maintained in the closed condition by a clamp. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 13 The sleeve may be maintained in the closed condition by a closing member. The sleeve may zip to the tarpaulin. The sleeve may zip to a patch on the tarpaulin. The sleeve may zip closed. The clamp may be formed from a rubber strip. The clamp may be formed from a plastic strip. The clamp may clamp the end of the tube against the patch. The clamp may stretch so that the end of the sleeve may be pushed between the strip and tarpaulin or patch. The strip may stretch so that the end of the sleeve may be pushed between the strip and tarpaulin or patch. The clamp may elastically resile to hold the end of the sleeve against the patch or tarpaulin. The strip may elastically resile to hold the end of the sleeve against the patch or tarpaulin. The clamp may be rigid. The strip may be rigid. The clamp may comprise two strips between which the sleeve is sandwiched when in the closed condition. The strips may be metal or plastic. The strips may be fastened together by wingnuts. One of the strips may be fixed to the tarpaulin or patch by positioning a nut on the inside of the cover. The nut may be separated from the tarpaulin be a fabric patch. The clamp may be attached to the sleeve. The sleeve may be self-supporting. The flexible member may be attached to an inner surface of a patch. The inner surface of the patch may be the surface that faces the tarpaulin. A pocket may be defined between the patch and tarpaulin. The flexible member may be stowed in the pocket when not in use. The flexible member may be drawn through the opening in the patch to allow access to the pile through the flexible member. The flexible member may be selectively drawn through each of the opening in the patch and the opening in the tarpaulin to allow access to the pile 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 14 through the flexible member. The cover may therefore be reversible (e.g. turned upside down) such that it may be turned over without requiring separate access points to be provided on both sides of the tarpaulin. An opening may be a slit. An opening may be sealable. An opening may be sealable by an adhesive tape. An opening may be sealable by a zip. The opening in the tarpaulin may be formed once the access point or vent has been attached to the tarpaulin. The opening in the tarpaulin may be formed and the access point or vent then be positioned over the opening on the tarpaulin. The opening in the access point may be formed once the access point or vent has been attached to the tarpaulin. The access point can be attached to the tarpaulin by sewing. The access point can be attached to the tarpaulin by welding. The join between the access point and tarpaulin may be covered by a protective layer. The protective layer may be tape. Each patch may be formed from a more robust (i.e. longer wearing) material than the tarpaulin. The access point may be supplied separately from the cover. The access point may constitute part of a kit. There may be provided a kit for creating a resealable access point, the kit comprising an access member for attachment to a tarpaulin at a point at which access through the tarpaulin is desired. The kit may comprise a sheet engagement member to which the access member is attached. The kit may comprise a sheet engagement member to which the access member is attachable. The sheet engagement member may comprise a patch. The sheet engagement member may be for attaching to the tarpaulin thereby to attach the access member to the tarpaulin. The kit may comprise a closing member for closing the access member when not in use. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 15 The kit may comprise a closing member for closing the access member when not in use. The closing member may comprise a clamp. The closing member may be attached to one or more of the tarpaulin, sheet engagement member and access member. The access member may be flexible so as to be accessible when the tarpaulin has a first face facing upwards - downwards may be in the direction of the pile beneath the tarpaulin. The access member may be able to be drawn through an aperture in the tarpaulin so as to be accessible when the tarpaulin has an opposite, second, face facing upwards. The components of the kit (e.g. access member and sheet engagement member where one is provided) may be attached to each other prior to sale. The cover may include an anchor system. An operator may be able to attach to the anchor system to maintain the operator on the dump. The anchor system may be attached to one or other side of the cover. The anchor system may be attached to both sides of the cover. The anchor system may comprise an attachment member attached to the tarpaulin. The anchor system may comprise an attachment member attachable to the tarpaulin. The attachment member may comprise a patch. The patch may be a fabric patch. An anchor may be attached to the attachment member. The anchor may comprise a strip of material. The material may be webbing material. The anchor may be attached to the attachment member at both ends of the anchor, with a portion of the anchor between the ends being not attached to the attachment member. The strip may be attached to the patch at opposite ends of the strip, with a portion of the strip between the opposite ends not being attached to the patch. The anchor may define a loop. The anchor may define an anchor point. The anchor may be adapted to be engaged by a carabiner. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 16 The anchor may be attached directly to the tarpaulin. Where the anchor is attached directly to the tarpaulin, and thus the anchor system may not require an attachment member. A running line may extend between multiple anchors. A running line may extend through multiple anchors. The running line may extend in a substantially straight line between anchors. The anchors may be aligned so that the running line extends in a substantially straight line. The cover may comprise multiple anchor systems. The cover may comprise multiple running lines. The or each running line may extend past a vent or access point. The running line may be connected to attachment points spaced from each other over the tarpaulin. The attachment points may be at opposite side of the tarpaulin. Each attachment point may comprise a shroud. Each attachment point may comprise a D-shackle. Each attachment point may comprise a D-shackle. The D-ring(s) may be sewn onto patche(s) on the tarpaulin. Each attachment point may be accessible from both sides of the sheet. The running line may be detachable and re-attachable to the attachment points. The anchor system may comprise one or more long strips of material extending, in use, over the dump. The anchor system may comprise one or more long strips of material extending, in use, along the dump. The strip may be formed from webbing material. The strip may be secured intermittently along its length to the tarpaulin. The intermittent securement of the strip to the tarpaulin may be at regular intervals. The intermittent securement of the strip to the tarpaulin may be at irregular intervals. The intermittent securement of the strip to the tarpaulin may create a plurality of anchor points along the strip at positions where the strip is not secured to the tarpaulin. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 17 A patch may extend the length of the strip between the strip and the tarpaulin. The anchor system may comprise a kit. The kit may include one or more sheet engagement members attachable to a tarpaulin. The kit may include one or more fixing points attached or attachable to a respective engagement member. A plurality of fixing points may be provided on a single sheet engagement member. The kit may include a running line. The running line may include fixing ends for attachment to an outermost fixing point. The kit may include a clip or ring, for cooperating with a respective fixing end, for attachment to the tarpaulin. Each fixing end may comprise a loop in the end of the running line. Each fixing end may comprise a clip in the end of the running line. A combination of different fixing ends may be provided on one running line. The cover may comprise a pull member for pulling the cover over the pile. The pull member may comprise a strip. The pull member may comprise one or more corner pulls enabling the tarpaulin to be dragged from a respective corner along the pile. The or each corner pull may be provided at a corner of a tarpaulin. The or each pull may comprise a free portion from which the pull can be pulled. The free portion may be disposed intermediate ends of the strip. The or each corner pull may comprise a sheet-engaging portion attached or attachable to the tarpaulin for transferring pulling force to the tarpaulin. The sheet-engaging portion may comprise two sheet-engaging parts, each part extending from the free portion to a respective end of the strip. The cover may comprise a central pull. The central pull may comprise a free portion and a sheet-engaging portion. Force applied to the free portion during pulling may be passed from the pull to the tarpaulin along a length of the sheet-engaging portion. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 18 There may be a combination of corner and central pulls. The pull member comprises a substantially V-shaped or U-shaped strip. The or each pull may comprise a webbing material attached in a V-shape to the tarpaulin. The or each pull may comprise a webbing material attached in a U-shape to the tarpaulin. Portions by which the or each pull is attached to the tarpaulin may extend from either end of the pull. Portions by which the or each pull is attached to the tarpaulin may extend from either end of the pull towards the middle of the pull. The free portion of the respective pull may be between the attached portions. The or each pull may comprise a strip of material. The free portion of a corner pull may extend from the fixed portions towards the corner of the cover. The free portion of a pull may extend in the direction in which the cover will be pulled by the respective pull. The free portion may be fixed in relation to the pile to retain the cover on the pile. The free portion of a pull may be configured to be anchored to the ground to retain the cover on the pile. The or each pull may be formed from an inelastic material. The or each pull may be formed from an elastic material. The cover may comprise a pocket for receiving a pull when the pull is not in use. The cover may comprise a reinforcing member positioned at or near a pull. The pocket may comprise the reinforcing member. The pocket may be formed from a polymeric sheet. The reinforcing member may be formed from a polymeric sheet. The or each pull may be attached to a patch that is attached to the tarpaulin. The or each pull may be attached to a strip that is attached to the tarpaulin. The cover may include a reinforcing strip or patch. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 19 The reinforcing strip or patch may extend parallel to an edge of the cover. The reinforcing strip or patch may extend along the edge of the cover. The reinforcing strip or patch may extend parallel to the edge, but spaced inwardly from the edge. The cover may comprise securing means between the reinforcing strip or patch and the edge of the tarpaulin. The securing means may comprise an eyelet. The reinforcing strip may extend at an angle to the edge of the cover. The reinforcing strip may extend from one corner of the cover in the direction of a diagonally opposite corner of the cover. The cover may comprise a restraint strap extending substantially the length of the cover. Free ends of the restraint strap may extend from the opposite ends of the cover. The cover may comprise a restraint strap extending substantially the width of the cover. Free ends of the restraint strap may extend from the opposite sides of the cover. The free ends may be securable to the ground to maintain the cover on the pile. The free ends may be attachable to a vehicle. A reinforcing strip may intersect the restraint strap so as to enable force to be transferred between the reinforcing strip and restraint strap. A reinforcing strip may extend around the periphery of the cover. A plurality of reinforcing strips may radiate at various angles from one corner of the cover. An attachment point may be positioned at the intersection from which the reinforcing strips radiate, for attaching to a guy rope. The attachment point may be a fixing device. The fixing device may be one of an eyelet, D-ring or O-ring. Loops may be provided on one or more edges of the cover, to afford pulling of the cover over the pile. Each loop may be formed by webbing. Each loop may be formed by intermittent attachment of a reinforcing strip along an edge of the cover. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 20 Disclosed herein is a cover for covering a pile, comprising: a sheet to overlay the pile; and a pull member comprising: a free portion from which the pull member can be pulled to pull the sheet over the pile; and a sheet-engaging portion attached or attachable to the sheet and extending away from the free portion along a surface of the sheet so that a force applied to the free portion during pulling is passed from the pull member to the sheet along a length of the sheet-engaging portion. There may also be provided a cover resulting from a combination of at least two of the various covers described above. Advantageously, embodiments of the present invention enable a cover to be safely and/or securely held in place regardless of prevailing weather conditions; whether the pile is being accessed (e.g. loaded or unloaded); or whether the pile changes in size over time. Embodiments of the present invention may also enable access to the pile or pile through the cover without requiring a slit or hole to be formed in the cover for each time the pile is intended to be accessed via through. Embodiments of the present invention may also enable a worker to secure themselves to the cover when working on the cover or pile to prevent the worker from tripping or falling from the pile. Brief Description of the Drawings Some embodiments of the present invention and other embodiments will now be described by way of non-limiting example only, with reference to the accompanying drawings, in which: Figure 1 is a plan view of a tarpaulin in accordance with an embodiment; Figure 2 is a side view of a tarpaulin in accordance with an embodiment, formed by joining three separate sheets; Figure 3A is a close-up view of a restraint of the tarpaulin shown in Figure 2; Figure 3B is a partial cross-section view of two tarpaulins joined together, and a restraint extending within the join; Figure 4 is a close-up view of an access point or vent in accordance with an embodiment, in an open condition; 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 21 Figure 5A shows the vent of Figure 4 in a closed condition; Figure 5B shows a clamping system for clamping a vent in a closed condition; Figure 5C shows a clamped vent on a cover that is in position on a pile; Figure 6 is a side cross-sectional view of an alternative vent in accordance with an embodiment, in a closed and stowed condition; Figure 7 shows a further closed condition of the vent of Figure 6 before being stowed in a storage pocket; Figure 8 is a side cross-sectional view of the vent of Figure 6 in an open condition with a sampler extending therethrough; Figure 9 is a plan view of the vent of Figure 6; Figure 10 is a side cross-sectional view of the vent of Figure 6 in an alternative open condition; Figure 11 is a close up view of an anchor point in accordance with an embodiment; and Figure 12 is a close-up view of an alternative embodiment of an anchor point in accordance with an embodiment. Figure 13 is a close-up plan view of a sleeve and restraint system; Figure 14 is a plan view of a tarpaulin in accordance with another embodiment Figure 15 is a close-up view of a corner portion of the tarpaulin of Figure 14 showing a corner pull; Figures 16 to 18 are close-up views of alternative corner portions of tarpaulins; Figures 19 to 24 are close-up views of reinforced corner portions of tarpaulins; and Figure 25 is a cross-sectional view of a tarpaulin having a restraint attached to either surface/side, to enable the tarpaulin to tied down regardless of which side of the tarpaulin faces upwardly. Detailed Description A cover 10, as shown in Figure 1, is used for covering a pile (e.g. a dump, stockpile or haystack). The cover 10 comprises a substantially rectangular polymeric sheet or body 12 that is fibre reinforced. The body 12 may be fabricated from any appropriate material and have any desired shape. For the 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 22 purpose of illustration, any item that may be referred to as a "sheet 12" or "body 12" will be referred to as a "tarpaulin 12" in the detailed description, though it will be appreciated that products and items falling within the scope of the more general term "sheet" are intended to be capable of substitution in place of the term "tarpaulin" in the present disclosure. The cover 10 includes a plurality of restraints 14 attached to the tarpaulin 12 at regular intervals along its length. The cover may also include an access point or vent 16 on the tarpaulin 12. The cover may also include an anchor system 18 to which an operator can attach to maintain the operator on the dump when the tarpaulin 10 is in use. The restraints 14 can be formed from webbing or any other appropriate material. A cover 19, as shown in Figure 2, comprises a tarpaulin 12 that overlays a pile to protect the pile from weather and pests. The cover 19 further includes a plurality of restraints 14 attached to the tarpaulin 12. A free portion 20 of each restraint 14 extends from the tarpaulin 12 (e.g. past the edge 22 of the tarpaulin 12 - see Figure 3A). The restrain 14 can be fixed in relation to the pile when the cover 19 is in use, thereby fixing the tarpaulin 12 in relation to the pile. Each restraint 14 further includes a sheet (i.e. "tarpaulin") contacting portion 24 that extends at least partially over the pile when the cover 19 is in use. A tarpaulin 12 may be formed from one or more separate sheets of material. For ease of description, where there are two or more sheets attached together to form a tarpaulin, those two or more sheets will be referred to as "subsheets": in other words, they are a sheet that constitutes less than the entirety of the body of the tarpaulin. The tarpaulin 12 shown in Figure 2 is formed from three subsheets 26, 28, 30 connected together (e.g. by welding or sewing) along connection lines X. The subsheets 26, 28, 30 are each 2m wide, though in general subsheets that form a tarpaulin need not have the same size or shape. Any down force applied to the restraints 14 when securing the tarpaulin 12 in position, will be applied to the tarpaulin 12 by the restraints 14 at the point where the restraints 14 are connected to the tarpaulin 12. This down force may also be applied by any wind loading during use of the cover 19. By extending at least partially over the dump when the cover 19 is in use, the restraints 14 distribute the load applied to the tarpaulin 12 over a greater portion of the tarpaulin 12 than is achievable using prior art restraint systems: prior art restraint systems generally attach only to an edge of a tarpaulin or are free straps that are 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 23 thrown over the tarpaulin and secured down on either side of the tarpaulin. In the case of straps sewn into edges of a tarpaulin, there is a significant amount of wear at the points at which the straps are tied down as the entirety of the tie down force is applied through those points. In the case of free straps thrown over the tarpaulin, such straps have no fixed portion, in contrast to the restraints 14 of the present disclosure, and can shift back and forward against the tarpaulin increasing wear. The restraints 14 of the present embodiment provide many advantages including a comparative reduction in wear of any particular portion of the tarpaulin 12. This reduction in wear may increase the working life of the cover 19. It may also add the ability to increase the load applied by the restraints 14 to the tarpaulin 12 without damaging the tarpaulin 12. This latter advantage can be particularly useful where the cover 19 is intended to be used in windy conditions or to compress material (e.g. silage) covered by the cover 19. In addition, since the cover 19 will often be unsecured at its edges while loading product onto or off the pile, the restraints 14 reduce the danger of the subsheet(s) 26, 28, 30 billowing up while workers are on the cover 19 since the restraints (e.g. straps) 14 can be loosened rather than only being capable of absolute attachment or detachment (i.e. one or the other, such as is the case where straps are directly attached to pegs in the ground). With reference to Figure 1, another exemplary method of using the present cover 10 during addition/removal of material from the pile is to release one or more restraints 14' at the end of the pile to/from which material is intended to be added/removed. The tarpaulin 12 is then folded back over itself, with the fold being positioned at or near a second restraint 14". The second restraint 14" is tensioned (e.g. by tightening a ratchet connected to its ends) to secure the tarpaulin 12 at the fold. The tarpaulin 12 is then tensioned open (i.e. secured in an open position) by securing the unsecured restraint 14' in a folded back position (e.g. where restraint 14' is in effect superimposed over restraint 14"'). This process reduces the likelihood that the tarpaulin 12 will move any appreciable amount during addition/removal of material from the pile, thereby also reducing the likelihood of injury to workers. Restraints 14 are positioned generally centrally on each subsheet 26, 28, 30 between the sides of the subsheet 26, 28, 30. However, since the weakest parts of the tarpaulin 12 will typically be where the subsheets 26, 28, 30 have been connected together, restraints 14 are also positioned on either side of each 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 24 join between the subsheets 26, 28, 30. This can potentially reduce stresses placed on those joins. The restraints 14 are substantially equidistantly spaced away from the join on either side. Alternatively, there may be a restraint 14 extending along the join on top of the subsheets 26, 28, 30 or, as shown in Figure 3B, within the join. Similarly, restraints 14 may extend along the cover 10 in a direction substantially perpendicular to the joins between the subsheets 26, 28, 30. The restraints may extend any other desired direction and position extending at least partially across the cover 10. The end subsheets 26, 30 may be tapered or folded towards their respective outer ends. As the width of the subsheets 26, 30 tapers towards the outer ends of the cover 10, the restraints 14 can be shortened towards those outer ends. Thus the length of the restraints 14 can be changed to suit the shape and configuration of the subsheets 26, 30, and of the cover 10 in general. Each of the restraints 14 of Figure 2 has two free portions 20 extending from the tarpaulin 12 at respectively different positions to be fixed in relation to the dump. In particular, each of the restraints 14 extends over the dump from one side of the tarpaulin 12 to the other so that the free portions 20 extend away from opposite edges of the tarpaulin 12. In this arrangement the sheet contacting portion 24 of each restraint 14 extends over the dump from at or near one side of the tarpaulin 12 to at or near an opposite side of the tarpaulin 12. Thus the sheet contacting portion 24 of each restraint 14, being the length of the respective restraint 14 between the two free portions 20 thereof, applies a uniform load across the width of the tarpaulin 12. It will be appreciated that the longer the sheet contacting portion 24 the greater the area over which force can be applied by the restraint 14 to the tarpaulin 12. The restraints 14 may extend from side to side of the tarpaulin 12. The restrains 14 may extend diagonally along the tarpaulin 12 or in any other direction. It is, however, preferred that the direction of extension of each restraint 14 remains substantially linear (e.g. in a straight line when the tarpaulin 12 is laid flat on the ground) as bends in the trajectory of the restraint 14 will result in variations in load applied by the restraint 14 to the tarpaulin 12 along the length of the restraint 14. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 25 The shape of the dump, though under the tarpaulin 12 in Figure 2, will be widely known and need not be discussed herein in detail. Each restraint 14, as shown in Figure 3A, further includes a sleeve 32 that is fixed to the tarpaulin 12. The sheet contacting portion 24 of the respective restraint 14 is received within the sleeve 32. The sheet contacting portion 24 can slide within the sleeve 32. Sliding of portion 24 within the sleeve 34 can enable adjustment of the length of the free portions 20 of the restraint 14. This is advantageous when the free portions 20 are anchored at different distances from the tarpaulin 12 as discussed below. The sleeve 32 has an opening 34 that delineates the end of the free portion 20 and the commencement of the sheet contacting portion 24. Unless the free portion 20 and sheet contacting portion 24 are in exact alignment (i.e. they form a straight line at the transition from the free portion 20 to the sheet contacting portion 24, and are preferably collinear throughout the sheet contacting portion 24) the opening 34 will experience greater force. Poor alignment can contribute to greater wear than other parts of the sleeve 32. The opening 34 is therefore reinforced to improve its longevity. The opening 34 may be reinforced by, for example, sewing or welding webbing material around the opening 34. The opening 34 may be reinforced by anchoring a metal ring to the end of the sheet contacting portion 24 at the opening 34. To prevent the free portion 20 from withdrawing or retracting entirely into the sleeve 32, the free portion 20 is provided with a stop 36. Any appropriate type of stop may be used. One stop may include a piece of rubber stitched (e.g. using a polytetrafluoroethylene thread sewn across the free portion 20 at position Y: such thread is capable of use in relation to the sewing of other features, such as patches 50 (discussed below) to the tarpaulin 12) to the webbing of the free portion 20 transversely to the free portion 20. The stop 36 is too wide to retract into the sleeve 32 and thus the free portion 20 can retract into the opening 34 only as far as the stop 36. The tarpaulin 12 and any or all parts of the restraint 14 may be formed from any appropriate material. The tarpaulin may be formed from polymeric materials that have high strength with only limited elasticity. Some elasticity is generally desirable so as to ensure that spikes in wind loads are damped. The elasticity should not, however, be so high as to enable the tarpaulin 12 to drift or be uncontrollable on the dump. Materials appropriate for patches, tarpaulins and 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 26 subsheets described herein include polyvinylchloride, polypropylene and polyethylene. Materials appropriate for patches, tarpaulins and subsheets may include woven fabrics having waterproof coatings. The sleeve 32 may be attached to the tarpaulin 12 in any appropriate manner, such as by welding or stitching. Similarly, the rubber stop 36 may be attached to the free portion 20 using any appropriate technique. The free portions 20 of the restraints 14 may be fixed in relation to the dump by any known means. One fixing method may include attaching the free portions 20 to pegs wedged into the ground. In the embodiment shown in Figure 2 the free portions 20 at the opposite ends of each restraint 14 in fact form one part of a ratchet system 39, the cooperating part of each ratchet system 39 being fixed to a base 38 under the dump. The operation and connection of such ratchet systems will be well understood in transport load securing operations, such as when securing a load to a flat bed truck. Save to say that the ratchet enables the progressive tightening of the restraints 14 onto the dump by drawing more of the free portion 20 of each restraint 14 into the ratchet. Similarly, the ratchet enables progressive loosening of the restraints 14 to enable addition of material beneath the cover 10. The ratchet may also enable controlled loosening of the cover 10 for removal from the pile. Since the restraint 14 has a free portion 20 at either end, each free portion 20 forms part of a different ratchet system. Tightening of the respective ratchets causes more of each free portion 20 to be drawn into the ratchet. Consequently, the length of the restraint 14 between the ratchets reduces as the ratchets are tightened. Tightening of the ratchets therefore increases the down force applied by the restraints 14 to the dump. Depending on the size of the dump and the uniformity or otherwise of its shape, the free portions 20 may be anchored (e.g. extend into a ratchet) at different distances from the tarpaulin 12. Since the sheet contacting portion 24 can slide within the sleeve 32 the restraint 14 can readily accommodate such differences in anchoring distance. The restraints 14 may alternatively not include a sleeve 32 but may instead each comprise a strip of, for example, webbing material extending at least part way over the dump and stitched or welded to the tarpaulin 12. The restraint 14 may be stitched or welded to the tarpaulin along the length of the strip or at the end of the respective strip remote from the end secured in relation 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 27 to the dump (e.g. the free portion 20). Though such an arrangement is less ideal than using restraints 14 that extend over the full width of the tarpaulin 12, the load applied by the restraints 14 to the tarpaulin 12 nevertheless remains distributed along the length of the respective strip of webbing material that is in contact with the tarpaulin 12. In this circumstance, a restraint may comprise a weldable PVC webbing welded directly to the tarpaulin 12, thereby eliminating the need for a sleeve 32. As a further alternative, the sleeve 32 may instead be formed at the join between adjacent subsheets 26, 28 that are connected together to form the tarpaulin 12, as shown in Figure 3B. In this case, the subsheets 26, 28 are connected (e.g. sewn or welded) along two substantially parallel lines 38', 38". The restraint 14 thus extends through the sleeve 32, which sleeve 32 is defined by both subsheets 26, 28 and the joining lines 38', 38" connecting those subsheets 26, 28. A cover 40, as shown in Figure 4, is used for covering a pile. The cover 40 comprises a tarpaulin 42 (area surrounding and beneath access point 16, hereinafter numbered 46) that overlays the pile in use. The cover 40 may comprises an opening or slit 44 (shown in broken lines) through which the pile is accessible. The cover 40 further includes a resealable access point 46 attached to the tarpaulin 42 about the opening 44. The access point 46 may be positioned anywhere on the tarpaulin 42: for example, the access point 46 may be positioned towards the middle of the tarpaulin 42 so that, when the cover 40 is in position on a pile, the access point 46 will be at or near the highest point of the tarpaulin 42. Positioning an access point 46 at or near the top of a dump facilitates venting of gasses and moisture laden warm air from the dump if necessary. The access point 46 comprises a flexible member, presently sleeve 48, attached to the tarpaulin 42. The sleeve 48 can be moveable between an open condition (see Figure 4) and a closed condition. In the open condition, the dump can be accessed. In the closed condition, access to the dump is prevented (see Figure 5A). The sleeve 48 is in register with the opening 44 (i.e. 'in alignment' so an implement such as a grain sampler can extend through both the sleeve 48 and opening 44 simultaneously thereby to access the dump) so that, when the cover 40 is in use, the dump can be accessed through both the sleeve 48 and 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 28 opening 44 together. The access point 46 may be positioned anywhere on the cover 40 as desired. The cover 40 may include any number of such access points 46. The sleeve 48 is a flexible tube that is fixed (e.g. by welding or sewing, for example, using the polytetrafluoroethylene thread mentioned above) to a substantially square fabric patch 50 that is in turn fixed to the tarpaulin 42. The join Z between the sleeve 48 and patch 50 may be reinforced to reduce the likelihood that repeated flexing of the sleeve 48 will result in cracks or other faults being formed at that join. The sleeve 48 may be fixed directly to the tarpaulin 42. However, the arrangement shown is preferred as it enables sleeves 48 of a standard size to be used regardless of the size of the opening 44, since the patch 50 can be tailored to cover the particular opening 44: this also enables the access point 46 to be retrospectively fitted to an opening or tear in an existing tarpaulin. While Figure 4 shows the flexible tube 48 in an open condition, Figure 5A shows the flexible tube 48 in a closed condition at the top T of the dump. In the closed condition the flexible tube 48 is at least partially flattened (e.g. against the patch 50) to shut the tube 48. The sleeve 48 may be flexible, yet heavy, so that it will tend towards laying flat against the patch 50. The sleeve 48 can be maintained in the closed condition by a closing member or clamp 52. Clamp 52 is formed from a rubber/plastic strip. The clamp 52 serves to clamp the end of the tube 48 against the patch 50. The strip 52 may be flexible so that it can stretch to enable an operator to push the end of the sleeve 48 between the strip 52 and tarpaulin 42 or patch 50. This arrangement may elastically resile to hold the end of the flexible tube 48 flat against the patch 50. The strip 52 may instead be rigid. The strip may allow sufficient friction between the tube 48 and clamp 52, and tube 48 and patch 50 or tarpaulin 42, to prevent the tube 48 from being inadvertently released from the clamp 52. An alternative clamp 53, as shown in figure 5B, includes two metal/plastic strips 53', 53" between which the flexible tube 48 is sandwiched. The strips 53', 53" are fastened together by wing nuts 53"'. One of the strips 53' is secured to the tarpaulin 42 or patch 50 in an appropriate manner (e.g. by positioning a nut on the inside of the cover 10, the nut being separated from the tarpaulin 42 by a small fabric patch so as not to damage the tarpaulin 42). The clamp 53 may alternatively be attached to the sleeve 48. The clamp may alternatively be freely 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 29 moveable (i.e. unattached except when clamped around the sleeve 48). It will, however, be appreciated that many different clamping or closing systems will be suitable for closing the sleeve 48, and clamping or closing systems can be made from any suitable material: all such systems and materials are intended to fall within the scope of the present disclosure. Figure 5C shows a vent or access point 46 in position on a tarpaulin 42 at the top of a pile or dump when the cover 40 is in use. The clamp 52, 53 may be attached to the patch 50 by any known method including those attachment methods mentioned above. In the embodiment of Figure 5C the sleeve 48 may even extend upwardly from the patch 50 at all times (e.g. being self-supporting). This upwardly orientated position enables access to the dump via the sleeve 48 upon removal/loosening of the clamp 52, 53. Alternatively, the configuration shown in Figure 5C may be an intermediate position of the sleeve 48 between a closed condition (e.g. as shown in Figure 5A), and an open condition enabling access to the dump through the sleeve 48. An alternative access point 54 is shown in Figure 6 in which a sleeve 56 is attached to an inner surface of a patch 58 (i.e. the surface of the patch 58 that faces the tarpaulin 60). The tarpaulin 60 (comprising subsheets 26, 28, 30) again includes an opening 62 (indicated by a dotted line) through which the pile is accessible. The patch 58 also includes an opening 64. The opening 64 defines a pocket 66 for housing the sleeve 56. The pocket 66 and consequently the sleeve 56, are thus located between the opening 64 in the patch 58 and the opening 62 in the tarpaulin 60. The openings 62, 64 are preferably slits. The opening 62, 64 can be sealed using tape or any other sealing method after having been used. When arranged as shown in Figure 6, the opening 62 in the tarpaulin 60 remains on the internal side of the tarpaulin 60 (i.e. on the side of the tarpaulin 60 facing the dump) so there is no need to apply tape to that opening. Instead, only opening 64 in the patch 58 need be sealed when the sleeve 56 is not in use. When the sleeve 56 is stowed in the pocket 66 a rubber clamp 68 (or alternative system such as clamp 52 or 53) is applied to the end of the sleeve 56 to hold the sleeve 56 in a closed condition. The rubber clamp 68 is formed by two pieces of rubber connected at their ends (e.g. by a fastener such as a metal crimp, or by welding or sewing). The rubber clamp can be biased towards being parallel with each other. The clamp 68 can therefore be opened by moving the 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 30 two pieces of rubber apart. The end of the sleeve 56 can be inserted therebetween. Release of the clamp 68 allows the two pieces of rubber come together to clamp the sleeve 56 shut either at its end or at some position intermediate its ends. Also when in a stowed condition tape 70 is placed over opening 64 to seal the opening 64. Sealing opening 64 can prevent ingress of contaminants and animals (e.g. birds). Once the tape 70 is removed the sleeve 56 can be drawn through the opening 64 as shown in Figure 7. The clamp 68 is then removed and the sleeve 56 can be opened. Opening the sleeve 56 can allow the access point 54 to be used. Opening 62 can be cut into the tarpaulin 60 at point 0 (Figure 7 shows the tarpaulin 60 at a point in time between opening of the pocket 66 by accessing opening 64, and cutting opening 62 into the tarpaulin 60 - note the clamp 68 is still in position in Figure 7 and would need to be removed to access the tarpaulin 60 at a point at which opening 62 is to be cut into tarpaulin 60). Each subsequent use of the access point 54 can enable an implement such as a grain sampler 71 to be extended sequentially through the opening 64, sleeve 56, opening 62 and into the dump (e.g. a stockpile of grain) beneath the tarpaulin 60 as shown in Figure 8. For the purpose of illustration, Figure 9 shows a plan view of the substantially square patch 58 stitched or welded to a tarpaulin 60 with tape 72 welded over the top of the joins between the patch 58 and tarpaulin 60. Since the access point 54 will experience use by an operator when accessing the dump, it is likely that the access point 54 will wear faster than other portions of the cover. Increased wear will also occur when, for example, birds peck the cover of a grain dump in the region of the patch 58 to collect grain that may have fallen when the operator last used the access point 54. The arrangement shown in Figures 6 to 8 can be turned upside down, as shown in Figure 10. The orientation shown in Figure 10 can enable the other side of the cover to face outwardly. The sleeve 56 can thus be selectively extended through either opening 62, 64 to enable access to the dump, depending on which side of the tarpaulin 60 is upwardly facing at the time access is desired. When upside down as shown in Figure 10, the opening 64 is positioned internally of the tarpaulin 60. In this orientation, the opening 64 need not be sealed when the sleeve 56 is not in use. In the same orientation, the opening 62 may now be sealed to prevent ingress of contaminants and pests. This 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 31 arrangement enables the tarpaulin to be turned over when the patch 58 or one side of the tarpaulin 60 becomes worn, thereby increasing the working life of the cover. The patches 50, 58 may also be made from a more robust material than the tarpaulin 42, 60. A more robust material may ensure that they wear at a rate comparable to that of the tarpaulin 42, 60 though they experience greater use than the tarpaulin 42, 60. This will ensure wear of the cover as a whole is substantially uniform. The opening 44, 62 in the tarpaulin 42, 60 may be cut when the respective access point 46, 54 is first being used. To achieve this, the sleeve 48, 56 of the access point 46, 54 is opened and a knife or blade is inserted through the open sleeve 48, 56 to cut the tarpaulin 42, 60. Alternatively, the opening 44, 62 may be cut in advance of the access point 46, 54 being positioned on the tarpaulin 42, 60. The access point 46, 54 is then positioned over the opening 44, 62. The access point can be attached e.g. by sewing or welding. The stiches or weld can be subsequently covered by tape. Positioning the access point 46, 54 over the opening 44, 62 may be less desirable since it relies on accurate positioning of the access point 46, 54, whereas cutting the tarpaulin 42, 60 through an already positioned access point 46, 54 ensures the opening 44, 62 is accurately positioned. The latter method, however, may result in damage to the access point 44, 62 if the operator cutting the respective opening 44, 62 slips with the cutting implement. It will be appreciated that any appropriate vent or access point may be used and still remain within the scope of the present disclosure. Preferably, however, whatever access point is used it should be resealable. The access point 46, 62 may be supplied in situ on a cover (e.g. cover 10). The access point 46, 62 may alternatively be supplied separately for fitting to, for example, an existing cover. To that end, a resealable access point 46, 62 may be provided for attaching to the tarpaulin 42, 60 at a point at which access through the tarpaulin 42, 60 is desired. The access point comprises an access member (e.g. sleeve 48, 56) attached to the tarpaulin 42, 60 and moveable between an open condition in which the pile can be accessed, and a closed condition for preventing access to the pile. The resealable access point 46, 62 may be positioned over an existing opening in the tarpaulin 42, 60. It may alternatively be positioned at a point on the tarpaulin 42, 60 at which access is 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 32 desired, the opening being cut into the tarpaulin 42, 60 after positioning of the resealable access point 46, 62. Such an access point may constitute part of a kit. For example, a kit for creating a resealable access point may be provided, the kit comprising an access member (e.g. sleeve 48, 56) for attachment to a tarpaulin 42, 60 at a point at which access through the tarpaulin 42, 60 is desired. The kit may further include a sheet engagement member (e.g. patch 50) to which the access member is attached or attachable. The sheet engagement member can be for attaching to the tarpaulin thereby to attach the access member to the tarpaulin. The kit may further include a closing member (e.g. clamp 52) attached or attachable to one or more of the tarpaulin, sheet engagement member and access member, for closing the access member when not in use. The access member may be flexible so as to be accessible when the tarpaulin has a first face facing upwards. The access member may also be drawn through an aperture in the tarpaulin so as to be accessible when the tarpaulin has an opposite, second, face facing upwards. To that end, the access member may be attached directly to the tarpaulin and/or sheet engagement member (if one is provided in the kit) on an outer side of the tarpaulin or sheet engagement member. The access member may also be attached to the tarpaulin or sheet engagement member at a position between the tarpaulin and sheet engagement member. For ease of use, the components of a kit (e.g. access member and sheet engagement member), or a subset thereof, will be attached to each other in an appropriate arrangement prior to sale. In the case of the reversible cover (e.g. as shown in Figures 6 and 10), anchor systems discussed hereafter, and restraint systems discussed above, may be attached to one or other side of the cover. The restraint systems may also be attached to both sides of the cover. In the particular example shown in Figure 3B the sleeve 32, and thus also the restraint 14, is commonly accessible (i.e. is suitably positioned for use to tie down or secure the cover 10) regardless of whether the cover 10 is the right way up or upside down. In such configurations the sleeve 32 may extend, between weld or stitching lines 38' 38", to opposite edges of the cover 10 so that the restraint 14 extends from the opposite edges. In other words, since the edges of the cover 10 are conveniently accessible irrespective of which face of the subsheets 26, 28 faces upwardly, 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 33 having the restraints 14 extend to the edges ensures they are also conveniently accessible irrespective of which face of the subsheets 26, 28 faces upwardly. Restraint systems may also be simply attached to both sides of one or more of the subsheets 26, 28, 30 so as to enable the tarpaulin 12 formed by those subsheets 26, 28, 30 to be readily reversed. Such a system is shown in Figure 25 in which a combination of different types of restraints 14', 14" is used. As shown, restraint 14' extends over the cover from one side to the other, with a free portion 20' at either end of the restraint 14' (only one free portion 20' being shown in Figure 25). Also shown is a sheet contacting portion 24' between the free portions 20'. On the opposite side or face of the tarpaulin 12', a restraint 14" is provided having only one free portion 20". On the opposite side or face of the tarpaulin 12', a fixed sheet contacting portion 24" extends part way over the pile in use. In a first configuration a first side 65' of the tarpaulin 12' will face upwardly and thus restraint 14' will be accessible and securable to maintain the tarpaulin 12' in position over a pile. In a second configuration a second side 65" of the tarpaulin 12' will face upwardly and thus restraint 14" will be accessible and securable to maintain the tarpaulin 12' in position over the pile. It will be appreciated that, in general, more than one restraint 14" will be necessary to ensure that the tarpaulin 12 is secured at both, opposite sides. For the case where a restraint 14', 14" is not in use it will be in contact with material constituting the pile. To prevent the restraint 14', 14" from degrading when in contact with that material it may be coated with a water resistant or waterproof coating. The restraints 14' and 14" may also be housed within a waterproof sleeve as discussed above in relation to restraints 14. The restraints 14' and 14" may also be housed within its respective free portion(s) 20', 20" may be received in a pocket (not shown) similar to pocket 114 discussed in relation to Figure 17. Referring now to Figure 11, a cover 74 is shown, the cover 74 being for covering a pile. The cover 74 comprises a tarpaulin 76 to overlay the pile when the cover 74 is in use. Due to the height of some piles and the steepness of the sides, operators on piles are at risk of injury if they fall: such is particularly the case where the dump is a haystack since the sides are sheer and often a number of metres high. To maintain an operator on the dump when the cover 74 is in use, the cover 74 further includes an anchor system 78 attached to the tarpaulin 76. An 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 34 operator can releasably attach to the anchor system 78. The anchor system 78 comprises a fabric patch 80 attached (e.g. by welding or sewing) to the tarpaulin 76. The fabric patch 80 is the same as, or similar to, the patches 50, 58 discussed above. A strip of webbing material 82 is attached at both ends (e.g. by stitching S) to the fabric patch 80. A portion of the webbing material 82 between its ends is not attached to the patch 80, thus defining a loop or anchor point 84 to which an operator can attach e.g. by latching a carabiner of a harness onto the anchor point 84. It will be appreciated that the strip of webbing material 82 may be sewn directly onto the tarpaulin 76. However, the size of the join between the webbing material 82 and tarpaulin 76 will be small when compared with the size of the join between the patch 80 and tarpaulin 76. Therefore the tarpaulin 76 is more likely to tear if the webbing material 82 is sewn directly thereto. Such a tear would enable ingress of contaminants and animals into the dump. It also means that the main cover is not compromised by stitching holes. Since the present strip of webbing material 82 is connected to the patch 80, tears will more likely form between the material 82 and patch 80 rather than between the patch 80 and tarpaulin 76. Since the patch 80 is applied on top of the tarpaulin 76 (i.e. there is no opening in the tarpaulin 76 below the patch 80) the dump will not be accessible through any tear that forms at the join between the patch 80 and webbing material 82. The operator may instead connect to a running line 86, as shown in Figure 12, that passes through multiple anchor points 84. The running line 86 extends in a substantially straight line between aligned anchor points 84. The running line 86 is connected at either end to the tarpaulin 76, respective anchor points 84 or respective patches 80. An operator may mount the dump by attaching a first carabiner or other catch to the running line 86 and walk up the dump. The first carabiner or catch will slide along the running line 86 until the next anchor point 84 is reached. A second carabiner or catch is then attached to the running line 86 on the side of the anchor point 84 opposite the first carabiner. The first carabiner is then detached and the operator can move further up the dump. A cover 10 may comprise multiple such running lines 86 as shown in Figure 1, extending in different direction across the cover 10. The running lines 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 35 86 preferably extend past any vents or access points 14, 46, 54 so as to provide easy access to those points 14 46, 54 when an operator is on the dump. The anchor system 78 may alternatively comprise one or more long strips of webbing material extending over and/or along the dump in use. The strip may be secured intermittently (i.e. at intervals, regular or otherwise) to the tarpaulin 76 thereby creating a plurality of anchor points 84 wherever a portion of the strip that is not stitched to the tarpaulin 76 is bounded by portions of the strip that are stitched to the tarpaulin 76. This arrangement can be less preferable to the arrangement previously described since it would, in practice, usually warrant the use of a continuous patch following the trajectory of the strip to ensure the likelihood of tears of the tarpaulin 76 are reduced. By way of contrast, the running line 86 may only require patches 82 under the locations of anchor points 84. Also, a running line may be connected to a shroud or attachment point (e.g. D-shackle) at opposite sides of the tarpaulin. Such a shroud arrangement could allow accessed from both sides of the sheet thereby enabling the running line to be readily attached to the opposite side of the tarpaulin in the event that the tarpaulin is turned over. As a further alternative, the anchor system may comprise stainless steel D-rings sewn onto patches on the tarpaulin. However, D-rings will generally be less desirable than webbing anchor points since the tarpaulin, when rolled for storage, may become damaged by the D-rings. The anchor system 78 may be provided in situ on a tarpaulin when sold. Alternatively, an anchor system 78 may be provided in a kit, for retrofitting to an existing tarpaulin. Such a kit for an anchor system may comprise one or more sheet engagement members (e.g. fabric patch 80). The kit may also comprise one or more fixing points (e.g. a strip 82 or a D-ring) attached or attachable to a respective engagement member, the respective engagement member being attachable to the tarpaulin (i.e. sheet) thereby to attach the respective fixing point to the tarpaulin (i.e. sheet). The kit may also include a running line and fixing ends (e.g. loops or clips in the ends of the running line) for attachment to an outermost (e.g. closest to an edge of the tarpaulin) fixing point. The kit may also include a corresponding clip or ring, such as a D-ring, sewn onto the tarpaulin. This may similarly be how any such running line could be attached. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 36 It will be appreciated that combinations exist (such as two fixing points for positioning on a single sheet engagement member) that are intended to fall within the scope of the present disclosure. The kit may further include accessories such as an operator belt or harness. The kit may further include accessories such as a cord and carabineer or other means for attaching to a fixing point or running line. Each of the components of the covers described herein, above and below, may be formed from any appropriate material. For example, the webbing material, restraints, running lines etc may be formed from 25mm webbing. The webbing material, restraints, running lines etc may be formed from 25mm belt. The webbing material, restraints, running lines etc may be formed from 25mm rope. The webbing material, restraints, running lines etc may be formed from sizes other than 25mm. It will usually be preferable to form the patches 50, 58, 78 from the same material as the tarpaulin 42, 60, 76 so as to facilitate attachment of one to the other. As mentioned above, each of the restraints 14 has two free portions 20 extending from the tarpaulin 12 at respectively different positions to be fixed in relation to the dump. In particular, each of the restraints 14 extends over the dump from one side of the tarpaulin 12 to the other so that the free portions 20 extend away from opposite edges 22 of the tarpaulin 12. In so doing, the sheet contacting portion 24 extends over the pile from at or near one side 22 of the tarpaulin 12 to at or near an opposite side 22 of the tarpaulin 12. The sheet contacting portion 24 of each restraint 14 slides within a sleeve 88. The sleeve 88 is welded or otherwise attached to the tarpaulin 12 and is open at either end. This arrangement allows the sheet contacting portion 24 to extend through, or between, the opposite openings of the sleeve 88. This arrangement also allows the free portions 20 of the restraint 14 extend away from the sleeve 88 from respective openings therein. With reference to Figure 13, the sleeve 88 may comprise a fixed portion 90 that is fixed in position relative to the tarpaulin 12. The sleeve 88 may further comprise a flexible portion 92 that extends from the fixed portion 90 of the sleeve 88 to the free portion 20 of the restraint 14. The flexible portion 92 moves with the free portion 20 towards and away from the fixed portion 24. The flexible portion 92 can be attached to the fixed portion 90 and free portion 20 by any known means. In the present case, the flexible portion 92 is 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 37 attached to be fixed portion 90 and free portion 20 by stitching. However, it will be understood that the sleeve 88 may be made from a relatively flexible material such that the flexible portion 92 is simply an extension of the same material forming fixed portion 90. The flexible portion 92 ensures that the opening 94 that would otherwise be formed in the sleeve 88 in the event that the flexible portion 92 is not used. In this position, the flexible portion remains closed. In the event that the flexible portion 92 is not provided, when the cover 10 is used with the surface to which the restraints 14 are attached facing upwardly, insects and pests can enter the sleeve 88. Covers 10 will often be flipped over from one season to the next. This is to reduce premature wearing of either side of the cover 10. Thus, any pests nesting in the sleeve 88 will have access to the dump when the cover 10 is flipped over. The flexible portion 92 prevents access to the sleeve 88. It may also enable the sleeve 88 to be evacuated by pulling on the free portion 20 of the restraint 14 to draw more of the restraint 14 out of the sleeve 88. The flexible portion 92 means pests cannot access the inside of the sleeve 88. Thus when the cover 10 is flipped over there are no pests that can escape the sleeve 88 into the pile. The flexible member 92 as shown may be replaced by any appropriate means for preventing access of pests and insects to the interior of the sleeve 88. For example, the sleeve-shape flexible member 92 may be replaced by an elasticised patch having a slit therein. The webbing of the restraint 14 may also slide through the slit, with the slit contacting (e.g. by slidable friction fit) both sides of the webbing at all times. A restraint 14 may be fitted to a cover 10 as supplied (i.e. in situ). However, it may also be convenient to supply restraints 14 for retrospective attachment to existing covers 10. To that end, a kit may be provided for forming a restraint for a cover. The kit may include a restraint (e.g. restraint 14) and restraint containment member (e.g. sleeve 88) for containing a portion of the restraint. The kit may also include a plurality of restraints and restraint containment members. Each restraint containment member may include a fixed portion (e.g. fixed portion 90) for fixing to a cover 10. Each restraint containment member may also include a flexible portion (e.g. flexible portion 92) attached or attachable to one or both of the fixed portion and respective restraint. For convenience one end of the restraint may be attached to the restraint 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 38 containment member. It can be useful to supply a restraint and restraint containment member pair attached together at only one end. This facilitates cutting of the restraint and restraint containment member at the opposite end to fit a particular cover. All kits described herein may further include the necessary supplies (e.g. needle, thread and tape) to facilitate attachment of the respective features to the cover 10. An alternative cover 94 for covering a pile is shown in Figure 14. The cover 94 comprises a tarpaulin 96 to overlay the pile, and a pull member 98. The pull member 98 comprises a plurality of corner pulls 100. Corner pulls 100 can be provided at each corner. Corner pulls 100 can enable the tarpaulin 96 to be dragged from its corners in either direction along a pile. A corner pull 100 may instead be provided at only one corner. The corner pulls 100 may be replaced by a central pull 102 (shown in broken lines). The corner pulls 100 may be replaced used in conjunction with a central pull 102 (shown in broken lines). It will be appreciated that any number and arrangement of pulls may be provided as desired, and all such arrangements are intended to fall within the scope of the present disclosure. The cover 94 is formed from a plurality of regularly shaped rectangular sub-sheets 104 welded (or otherwise attached) together along respective long edges of the sub-sheets 104. The cover 94 is substantially rectangular in shape to extend over a substantially rectangular dump. A corner pull 100 as shown in Figure 15 comprises a free portion 106. The corner pull 100 can be pulled by a free portion 106 to pull the tarpaulin 96 over the pile. Each corner pull 100 further includes a sheet-engaging portion 108 attached or attachable to the tarpaulin 96. Each corner pull 100 may extend away from the free portion 106 along the surface of the tarpaulin 96. In such an orientation, a force applied to the free portion 106 during pulling is passed from the corner pull 100 to the tarpaulin 96 along a length of the sheet-engaging portion 108. The corner pull 100 may be one of many pulls that are positioned anywhere on the tarpaulin 96. The corner pulls 100 may together constitute a pull member 98 as discussed above. It may also comprise a strip 110 of webbing material welded (see reference 112) in a U- or V-shape to the tarpaulin 96. The welded portions 108 of the strip 110 extend from either end of the strip 110 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 39 towards the middle of the strip 110, with a free portion 106 between the welded portions 108. As the free portion 106 is pulled, force applied to the free portion 106 (e.g. by a vehicle attached by a rope to the free portion 106) is transferred from the free portion 106 to the welded portions 108, and from the welded portions 108 to the tarpaulin 96. Thus the force applied to the free portion 106 is distributed along the length of the welded portions 108. This reduces the likelihood of tearing or damage to the tarpaulin 96 due to force concentrations during dragging of the cover 94 over the pile. The free portions 106 extend from the fixed portions 108 towards a corner of the cover 94. However, the free portions 106 may instead extend along the cover 94 in the direction of which the cover 94 will be dragged. The free portion 106 may have any other orientation as desired. Once the cover 94 is in position, the free portions 106 may be anchored (e.g. by Guy-ropes) to the ground to serve as anchors for retaining the cover 94 on the pile. The free portion may be fixed in relation to the pile. The corner pull 100 is formed from a webbing material that is substantially inelastic. This is so that, in the event that a corner pull 100 breaks or comes loose during pulling it will not spring back and endanger operators or damage the cover 94. In some cases, however, elastic or slightly elastic webbing may be used. This is so that the free portion 106 can be stretched around a peg or anchor to secure a corner of the cover 94 when the cover 94 is in position on the pile. The cover 94 may be provided with a corner pocket 114 fixed to one side of the tarpaulin 96 as shown in Figure 16. The corner pockets 114 may be used if it is not desired that the free portions 106 be used to anchor down the corners of the cover 94. The corner pockets 114 may also be used when there is a likelihood that the free portions 106 will become damaged if left exposed when the cover 94 is in position on a pile. The corner pocket 114 comprises a right-angled triangle-shaped patch of fabric the orthogonal edges of which are parallel to edges of the tarpaulin 96. The orthogonal edges are welded or otherwise attached to the tarpaulin 96. The diagonal edge of the corner pocket 114 remains unattached and the patch thereby forms a triangular pocket in which the free end 106 is housed when not in 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 40 use. The corner pocket 114 prevents the free end 106 from flapping in the breeze, or rubbing in the dirt when the free end 106 is not in use. The corner pocket 114 also serves to reinforce the corner of the cover 94. Rather than, or in addition to, corner pocket 114 a reinforcing patch 116 can be provided as shown in Figure 17. The reinforcing patch 116 is welded or otherwise attached to the tarpaulin 96 along its edges or alternatively over its entire surface. The corner of the tarpaulin 96 is reinforced by the fabric patch 116 and will be less likely to tear when compared with a corner that has not been reinforced. This is beneficial if the corner of the tarpaulin 96 is scrunched up and tied to a vehicle so that the cover 94 can be dragged over a pile. Similar to corner pocket 114, reinforcing patch 116 is in the shape of a right-angled triangle. However, the corner pocket 114 and reinforcing patch 116 may be any appropriate shape as desired. It may also cover both sides of the tarpaulin 96 rather than being positioned on only one side thereof. The corner pocket 114 and reinforcing patch 116 may be any appropriate material. The corner pocket 114 and reinforcing patch 116 may be formed from a polymeric sheet. An alternative pull member or corner retainer 118 is shown in Figure 18. The corner retainer 118 again comprises a corner pull. In this embodiment, the corner pull 118 includes a strip or strips of webbing material 120. The webbing material 120 is/are sewn onto a respective rectangular strip or patch of fabric 122. The strip or patch of fabric 122 is welded onto the tarpaulin 96 of the cover 94. The U-shaped or V-shaped arrangement of the present pull member 118 is similar to that of the previous pull member 98. This corner retainer 118 is particularly useful where the webbing material 120 cannot readily be welded to the tarpaulin 96. Since the webbing material 120 is sewn to the fabric 122, no welding is required of the webbing material 120. Also, while the webbing material 120 of the present embodiment has been sewn to the fabric 122, any other appropriate method can be used in place of sewing. Corner retainer 118 is also useful where greater tensions are to be placed on the webbing material 120 than would be expected with the corner retainer 98 of Figure 15. In this regard, the fabric patch of Figure 18 distributes the force applied to the corner retainer 118 over a larger surface area of the tarpaulin 96, 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 41 namely the surface area of patches 122, than is achieved using the corner pull 98 of figure 15. A significant amount of force will be applied to the corners of the cover 94 through the corner retainers 100, 118 when drawing the cover 94 over a pile. Thus the corners and edges of the cover 94 can be strengthened as shown in Figures 19 to 24: these figures show some of many variations in reinforcement and strengthening strips and patches, and all such variations are intended to fall within the scope of the present disclosure. In Figure 19, a reinforcing webbing strip 124 has been welded to either an underside or on top, or both, of the tarpaulin 96 of the cover 94. It will be appreciated that such reinforcement may also be supplied in circumstances where no pull member 98 is provided. While reinforcing webbing strip 124 is directly attached to the tarpaulin 96 it may be instead sewn to a fabric patch that is then welded to the tarpaulin 96. This variance will be understood to be applicable wherever webbing material, reinforcements and similar are used in relation to the tarpaulins described herein and those incorporated by reference. The reinforcing strip 124 extends parallel to the edge 126 of the cover 94. The reinforcing strip 124 can extend either along the edge 126 or spaced back from the edge 126 as shown. By spacing the webbing 124 back slightly from the edge 126 it is less likely that the webbing 124 will be damaged when the edges 126 of the cover 94 are damaged (e.g. by dragging along the ground). It also provides room to attach other securing means (e.g. retaining eyelets - not shown) in the cover 94 between the reinforcing webbing 124 and the edge 126 of the cover 94 by which the cover 94 can be secured over a dump. Spacing the webbing 124 back from the edge 126 can also facilitate clamping of the cover to a bunker wall or other structure, by providing a free portion of material between the webbing 124 and edge 126. An alternative reinforcing arrangement is shown in Figure 20, in which an edge or side reinforcing strip 124 has been applied similar to that shown in Figure 19. An additional strip 128 has been welded to the tarpaulin 96 to extend substantially diagonally across the cover 94 towards the corner 130. The angle of the diagonal strip 128 relative to the edge 126 of the tarpaulin 96 may be any desired angle. In the present case the diagonal strip 128 extends from the corner 130 in the general direction of the diagonally opposite corner of the rectangular tarpaulin 96. The angle of the diagonal strip 128 will depend inter alia on the 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 42 positions of other reinforcements on the tarpaulin 96, where the tarpaulin 96 is to be tensioned when in position over a dump, and where it is anticipated that tensions will arise in the tarpaulin 96 as a result of any prevailing wind. Yet a further alternative is shown in Figure 21, in which a restraint strap 132 has been welded along an edge 126 of the tarpaulin 96, and the reinforcing strip 124 intersects the restraint strap 132. The restraint strap 132 runs generally along the entire length of the cover 94. The restraint strap 132 has free ends 134 extending from opposite ends of the cover 94. The free ends 134 of the restraint strap 132 can be secured to the ground by any known means (e.g. a peg or as part of a ratchet strap the cooperating component of which is anchored in relation to the pile) to hold the cover 94 on the pile. The free ends 134 can also be attached to a vehicle (or similar) so that the vehicle can be used to drag a cover 94 over the pile. The restraint strap 132 is substantially parallel with a lengthwise edge of the tarpaulin 96. If the cover 94 is to be dragged from the centre of a particular side (e.g. as would be the case in respect of pull member 102 in Figure 14) the restraint strap 132 may extend from a side. The restraint strap 132 may also extend from a corner of the tarpaulin 96 to a position substantially centred on the side of the tarpaulin 96 from which the cover 94 is to be pulled over the pile. Since the reinforcing strip 124 intersects (and is connected to) the restraint strap 132, there is a continuity of force around the corner 130 of the cover 94. By way of contrast, if the restraint strap 132 and reinforcing strip 124 were not to intersect, any force applied to the reinforcing strip 124 would have a concentration about the end of the reinforcing strip 124. This would weaken the tarpaulin 96 in the region of the end of the reinforcing strip 124. It will be appreciated that a similar interconnecting characteristic can be gained by welding reinforcing strips 124 around or near the entire perimeter edge 126 of the cover 94. This arrangement allows force applied to any edge 126 of the cover 94 to be appropriately distributed. Figure 22 shows yet a further alternative embodiment in which there are a plurality of reinforcing strips 136 at various angles radiating from the corner 130 of the cover 94. At the point at which the reinforcing strips 136 meet (i.e. at the corner 130 of the cover 94) there is an eyelet 138 for connecting a guy-rope or like device to the cover 94. The eyelet 138 can secure the cover 94 in position with the aid of guy-rope. Moreover, a webbing loop could be passed through the 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 43 eyelet 138, providing a handle for tensioning the cover 94 over a pile, or pulling it into position. It will be appreciated that eyelets 138 may be substituted for any appropriate fixing device, such as a D-ring or O-ring, and all such alternatives are intended to fall within the scope of the present disclosure. In a similar manner, to afford pulling and anchoring of a tarpaulin webbing loops, or loops made from any other appropriate materials, may be sewn into one or more edges of the tarpaulin 96. Such loops may also be formed by discontinuous/intermittent sewing or welding of a reinforcing strip parallel to an edge of the tarpaulin 96: the portions of the strip that are not sewn to the tarpaulin 96 effectively form loops to which ropes and straps can attached to afford pulling and anchoring of the tarpaulin 96. Moreover, the loops may be formed anywhere on the tarpaulin 96 (not just at the edges or parallel to the edges). For example, loops or sleeves may be formed (e.g. by welding or sewing webbing, fabric or polymeric strips on the tarpaulin 96 - it should be noted that such materials may be used herein for any strip, webbing, restraint etc) across the tarpaulin 96 from side to side at intervals along the length of the tarpaulin 96. Such a configuration may result in loops or sleeves being formed, for example, along the lines of join between adjacent sub-sheets 104 as shown in Figure 14. Pipes or structural members can be inserted through such loops or sleeves (or the loops may be attached, such as by a hook and loop fastener system (e.g. Velcro®), about the pipes or structural members) to form ribs spaced along the tarpaulin 96. The pipes or structural members serve as a support to maintain a shape of the cover 94. The pipes or structural members can also support the cover 94 when pulling it over the dump or holding the cover in position once installed. In addition to these substantially linear reinforcing strips 136, the cover 94 of Figure 22 includes a large quarter-circle fabric reinforcing patch 140 welded to the tarpaulin 96 over its entire surface. The radial lines of the quarter-circle patch 140 are parallel, and coincide with, edges 126 of the tarpaulin 96. The patch 140 reinforces the corner of the tarpaulin 96. The patch 140 can also serve to spread the load (i.e. tensile forces) applied at the corner. Similarly, loops formed along the edges of the tarpaulin 96 may be looped around a pipe. A pipe may be inserted into a sleeve sewn or otherwise formed in the edge of the tarpaulin 96, so that the pipe facilitates distribution of load along the tarpaulin 96. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 44 The patch 140 may be provided on the same side, or the opposite side, of the tarpaulin 96 to the reinforcing strips 136. It may also be provided for reinforcement even where no reinforcing strips are used. The patch 140 may also be welded only along its edges or in a pattern as appropriate. The patch 140 may have any desired shape. For example, rather than having a quarter-circle shape, the fabric patch may have a rectangular shape as identified by 142 in Figure 23. Two of the four sides of the patch 142 are, similar to the patch 140, coincident with and parallel to sides 126 of the tarpaulin 96. A further alternative embodiment is shown in Figure 24, in which reinforcing strips 144 have been welded along substantially the entire length of tarpaulin 96. From this and the other Figures, it will be appreciated that any number and arrangement of reinforcing strips and patches. These arrangements may be on one or both sides of the cover 94 or tarpaulin 96. They may be used to provide appropriate strength to the cover 94 or tarpaulin 96 to enable it to withstand being pulled over a pile. They may also be used to withstand tensions applied to retain the cover 94 or tarpaulin 96 over the pile. For example, there may be only one corner pull 98, 118, or side pull 102. In general, the reinforcing strips and patches serve to distribute forces that would otherwise be concentrated. For example, in Figure 22 a force applied to the loop, ring or eyelet 138 will be distributed by the radiating reinforcing strips 136 outwardly from the corner 130 across a large area of the cover 94. In another example, in Figure 21 the side reinforcing strip 124 will distribute along the respective side 126 of the cover 94 a load applied to a point on that side 126 of the cover 94. It will be appreciated that materials described herein, such as webbing used for strips 124 and 144, and polytetrafluoroethylene thread for sewing members together, may be substituted for any appropriate material. For example, the webbing may be substituted for rope welded, sewn or otherwise attached to the edge of the sheet or body of the cover. All such variations in materials and methods for their attachment together, are intended to fall within the scope of the present disclosure. It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the spirit and scope of the invention. In the claims which follow and in the preceding description of the 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015 45 invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. 6783993 1 (GHMatters) P90038.AU.4 NICOLAL 11/08/2015