Abstract:
A relocatable oil sand slurry preparation system is provided for preparing an aqueous oil sand slurry amenable to pipeline conveyance while producing minimum overall rejects, comprising (a) a relocatable rotary digester for slurrying oil sand and water and digesting oil sand lumps to form a pumpable slurry, the rotary digester having a feed end for receiving oil sand and water, a slurrying chamber comprising a plurality of lifters for slurrying the oil sand and water, and a trommel screen end for screening out oversize rejects from the oil sand slurry which falls through the trommel screen; and (b) a relocatable rejects recirculation unit operably associated with the rotary digester for receiving oversize rejects and delivering the rejects back to the rotary digester for further digestion. In a preferred body, relocatable oil sand slurry preparation system further comprises a rejects crusher for crushing oversize rejects prior to delivering rejects back to the rotary digester.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to mining technology and a method for the processing of recovered bitumen bearing oil sands from the earth. More particularly, the invention relates to a mobile system of equipment for increasing the efficiency of the ore mining operation. 
       BACKGROUND OF THE INVENTION 
       [0002]    The Northern Alberta Tar Sands are considered to be one of the world&#39;s largest remaining oil reserves. The tar sands are typically composed of about 70 to about 90 percent by weight mineral solids, including sand and clay, about 1 to about 10 percent by weight water, and a bitumen or oil film, that comprises from trace amounts up to as much as 21 percent by weight. Typically ores containing a lower percentage by weight of bitumen contain a higher percentage by weight of fine mineral solids (“fines”) such as clay and silt. 
         [0003]    Unlike conventional oil deposits, the bitumen is extremely viscous and difficult to separate from the water and mineral mixture in which it is found. Generally speaking, the process of separating bitumen from the tar sands comprises six broad stages. 1) Initially, the oil sand is excavated from its location and passed through a crusher or comminutor to comminute the chunks of ore into smaller pieces. 2) The comminuted ore is then typically combined with hot process water to aid in liberating the oil. The combined tar sand and hot water is typically referred to as a “slurry”. Other agents, such as flotation aids may be added to the slurry. 3) The slurry is then passed through a “conditioning” phase in which the slurry is allowed to mix and dwell for a period to create froth in the mixture. The term “conditioning” generally refers to a state whereby the slurry is sufficiently mixed and aerated that a commercially viable amount of the bitumen has left the mineral component to form an oily film over the bubbles in the slurry. 4) Once the slurry has been conditioned, it is typically passed through a series of separators for removing the bitumen froth from the slurry. 5) After the slurry has been sufficiently processed to remove the maximum practical amount of bitumen, the remaining material, commonly known as the “tails”, is typically routed into a tailing pond for separation of the sand and fines from the water. Due to the time required to clarify the tailings water, the process requires the continual addition of fresh water. 6) The separated bitumen and water is then delivered to a secondary extraction process that further removes mineral and water content and provides a diluted bitumen product for delivery to an upgrader that converts the bitumen into a commercially usable product. 
         [0004]    It has been recognized for a long time that, since the bitumen comprises a relatively small percentage by weight of the ore initially extracted, separation of the mineral content from the ore as soon as possible after excavation would lead to the most efficient and cost effective mining process. It has also been recognized that it would be useful to immediately recycle the process water used to create the slurry rather than the current requirement of continually using fresh water due to the slow process of clarifying tailings water. While these advantages have been known, to date there has been no commercially viable method of extracting the mineral content soon after excavation and recycling the process water. Generally, the sand and fines settle out of the tails at different rates with the fines taking a long time to settle out. This results in a tailings pond comprised of a sand deposit, a suspension of fines and water, and a thin layer of clarified water on the top of the tailings pond. While the thin layer of clarified water is clean enough that it may be siphoned off and recycled as process water, the bulk of the water remains trapped in the suspension. Furthermore, as settling progresses, the settled fines trap a significant percentage by weight of water. The net result has been extensive tailings ponds that require significant containment structures and associated ongoing maintenance as well as increasing transportation costs as the tails must be transported to new tailings deposition sites as existing ponds are filled. Handling the tails and transporting them to available tailings ponds has become a difficult and expensive logistical problem in mining the oil sands. Additionally, a large volume of water is tied up in existing ponds, necessitating a large ongoing demand for fresh process water. 
         [0005]    Over the years, a variety of methods have been used to process and transport the sand from the excavation site. Initially, oil sand excavation and transport were completely mechanical via conveyor belts extending from the mine face to a large facility for processing the mined ore. As mining progressed the conveyors lengths were increased to transport ore from the receding mine face to a large processing facility. The use of conveyors led to many difficulties including high energy costs and mechanical breakdown which led to work stoppage. As mining continued, the use of conveyors to transport the ore over extended distances became unworkable. 
         [0006]    Large ore trucks were instituted to replace the conveyor system for transporting ore from the mine face to the processing facility. The ore trucks, however, are expensive to purchase and operate and often create inefficiencies in the production process. 
         [0007]    As described in Canadian Patent No. 2,029,795, it was determined that it was preferable to deliver the ore by truck from the mine face to an intermediate site where the ore would be crushed and combined with hot process water at a slurry preparation facility to create a pumpable slurry for transport through a pipe. This “hydro-transport” process served the dual purpose of efficiently transporting the slurry from an intermediate site relatively near the mine face to the large processing facility and allowing time for the slurry to be sufficiently conditioned on route. Provided the hydro-transport was over a sufficiently large enough distance that the dwell time in the pipe was sufficiently long, typically at least 1 kilometre, the slurry would arrive at the processing facility already conditioned and ready for separation. Thus, the previously required separate conditioning step could be omitted from the process. 
         [0008]    While the hydro-transport solved some of the difficulties with transporting the ore from the mine site face to the separation facility, it did not solve the long term need to reduce the mechanical transport of large volumes of mined oilsand from the mine face to the intermediate site. As will be appreciated, continual excavation results in the active mine site face being located further and further from the crusher and slurry preparation facility. Solutions to date have typically relied on constructing longer conveyor belts to transport the ore, or use additional trucks, to move the ore from the mine face to the slurry facility at the intermediate site. Though these solutions provide temporary relief, they do not solve the inefficiency of transporting the mineral component further than required. 
         [0009]    One concept was to do away with the transport step completely by locating all of the ore processing machinery near the mine face. An example of this concept is disclosed in Canadian Patent No. 2,092,121 and Canadian Patent No. 2,332,207. These references disclose a single mobile excavator and bitumen extraction facility, commonly referred to as a tar sand combine, that follows the mine face as digging progresses. This solution is not ideal as it requires the continuous transport of a large amount of extremely heavy machinery and water including a slurry preparation facility. In addition, connections to the hydro-transport pipeline and process water supply line must be continuously extended as the combine advances. Further, some embodiments suggest separating the mineral component at the mine face. Since the slurry must first be conditioned prior to separation, these embodiments require the continual transport of large volumes of slurry as it is conditioned. 
         [0010]    In Canadian Patent Application No. 2,453,697, the idea of a process line comprising a combination of mobile and relocatable equipment units at the face of an oil sand mine site is suggested. The &#39;697 application proposes a process comprising a mobile excavator that advances along a mine face, a mobile comminutor that advances behind the excavator to crush the mined ore to a conveyable size, and a relocatable conveyor that extends along the mine face for receiving the crushed oil sand and conveying it to a relocatable slurry facility for preparing slurry for hydro-transport. The slurry facility may be connected directly to a fixed pipe for hydro-transport. The process line of the &#39;697 application allows for relatively small components, such as the excavator and comminutor, to be mobile and follow the mine face as digging progresses. Less transportable equipment such as the slurry facility and hydro-transport pipe, are relocatable. That is, they are stationed in a fixed location for an extended period of time (months), but may be relocated once the excavator has removed all of the ore within near proximity to the relocatable conveyor. 
         [0011]    The disclosure of the &#39;697 application suffers from several limitations. First, the dwell time of the slurry facility is determined solely by the rate of excavation and the length of the first relocatable conveyor. Thus, to increase the dwell time in a particular location, either the rate of excavation must be slowed or the length of the conveyor must be increased. The Northern Alberta region has extremely harsh weather conditions and it has been found that extensive conveyors consume a considerable amount of energy, and are prone to break down resulting in work stoppage. For this reason, the length of the conveyor is preferably not overly long. However, it is also desirable that the slurry facility be relocated as seldom as possible necessitating a minimum length of conveyor in order to access a suitable volume of ore to supply the slurry facility. An additional limitation of the &#39;697 application is that a practical relocatable slurry facility or relocatable desanding facility is not disclosed. 
         [0012]    A further problem faced by the industry is the extensive use of water to extract the bitumen from the ore. While the sand portion of the mineral component may be practically removed from the slurry, the fine tailings, clay and other fine-sized material, is difficult to remove from the tailings and tends to remain in suspension. The solution to date has been to store the tailings in ponds for a sufficient period to allow the fines to settle out of the water. It has been determined, however, that it takes an extremely long period of time for the fines to settle out, resulting in ever increasing tailings ponds. Additionally, water becomes trapped in the interstitial spacing between particles so that even after the fines have settled a large amount of water is trapped in the settled material. Other than the excessive water requirements, tailings ponds create an environmental and logistical challenge as tailings must be continually disposed of in the continuously growing volume of tailings ponds which must be contained and maintained for years. There thus exists a need for a method of processing oil sands that obviates the need for extensive tailings ponds and provides for the recycling of water from the tails soon after deposition at a deposition site. 
         [0013]    A further limitation of the prior art is that there is no practical solution provided for handling tailings. Rather, current deposition methods result in a separation of a course tails and a fine tails, maintaining the need for extensive tailings ponds to provide settlement of the fine tailings component. There thus exists a need for a method of processing oil sands that produces a whole dry tails comprising both the sand component and the fine tailings. 
         [0014]    There thus exists a need to increase the efficiency of excavation and transport processes to reduce operating costs. There exists an additional need to increase the operating period for an excavator servicing a transportable slurry facility, without increasing the distance of ore transport from the excavator to the facility. There exists a further need for a process capable of removing the mineral component of the oil sands at a proximate location to the mine face without the creation of extensive tailings ponds. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    In drawings which illustrate by way of example only a preferred embodiment of the invention, 
           [0016]      FIG. 1  is an illustration of an embodiment of the process of the present invention. 
           [0017]      FIG. 2  is a top view illustration of an embodiment of the process line of the present invention. 
           [0018]      FIG. 3  is a top view illustration of an embodiment of the present invention. 
           [0019]      FIG. 4  is a side view illustration of an embodiment of the present invention. 
           [0020]      FIG. 5  is a side view illustration of an embodiment of the present invention. 
           [0021]      FIG. 6  is a side view illustration of an embodiment of the present invention. 
           [0022]      FIG. 7  is a side view illustration of an embodiment of the present invention. 
           [0023]      FIG. 8  is a side view illustration of an embodiment of the present invention. 
           [0024]      FIGS. 9   a - 9   c  are top view illustrations of an embodiment of the present invention. 
           [0025]      FIGS. 10   a - f  are top view illustrations of an embodiment of the present invention. 
           [0026]      FIG. 11  is a top view illustration of an embodiment of the present invention. 
           [0027]      FIG. 12  is a process illustration of an embodiment of the present invention. 
           [0028]      FIG. 13  is an isometric illustration of an embodiment of the present invention. 
           [0029]      FIG. 14  is a side view illustration of an embodiment of the present invention. 
           [0030]      FIG. 15  is a bottom view illustration of an embodiment of the present invention. 
           [0031]      FIG. 16  is a side view illustration of an embodiment of the present invention. 
           [0032]      FIG. 17  is a schematic view showing an embodiment of a modular, mobile extraction system according to an aspect of the present invention incorporating a plurality of mobile cyclone separation stages forming a mobile cyclone separation facility and a mobile froth concentrator vessel defining a mobile froth concentration facility. 
           [0033]      FIGS. 18   a  to  18   f  are schematic plan views showing embodiments of the present invention. 
           [0034]      FIGS. 19   a  to  19   c  are schematic plan views showing embodiments of the present invention. 
           [0035]      FIGS. 20   a  and  20   b  are schematic plan views showing an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0036]    In one aspect the invention provides a process line for mining an oil sands ore body, the process line comprising an excavator for mining oil sands ore; a comminutor for receiving mined ore from the excavator, comminuting the mined ore to conveyable size and transferring the comminuted ore to a mobile conveyor for transporting the comminuted ore; the mobile conveyor having a free end, a discharge end and at least one drive for advancing the conveyor through an operational arc generally about the discharge end; whereby the excavator mines a section of ore within operational reach along the length of the mobile conveyor and supplies the mined ore to the comminutor, and the comminutor supplies conveyable ore to the mobile conveyor, and whereby the mobile conveyor is periodically moved about the discharge end to locate another portion of the ore body within operational reach of the mobile conveyor until substantially all of the ore body within the operational arc has been mined. 
         [0037]    In a further aspect the invention provides a mobile conveyor for transferring mined oil sands ore from a mine face, the conveyor comprising: two or more conveyor sections; each of the two or more sections having at least one drive for advancing the conveyor, and at least one alignment device for detecting misalignment between at least one adjacent section and controlling the drive responsive to a detection of misalignment to align adjacent sections. 
         [0038]    In a further aspect the invention provides a method of mining oil sands ore with a mobile conveyor, the method comprising: 
         [0039]    at a first conveyor position:
       excavating and sizing ore at a mine face within operational reach of the first position;   transferring the sized ore to the conveyor;   conveying the sized ore along the conveyor; and   discharging the sized ore;   after excavating, sizing and transferring substantially all the ore within operational reach of the conveyor in the first conveyor position, advancing the conveyor generally about the discharge end to a second conveyor position; and, excavating, sizing and transferring substantially all the ore within operational reach of the conveyor at the second position.       
 
         [0045]    In a further aspect the invention provides a method of mining oil sand ore with a mobile conveyor, the method comprising: excavating, sizing and transferring to the conveyor all ore within operational reach along the length of the conveyor; conveying the sized ore along the conveyor to a discharge end of the conveyor; advancing the conveyor generally about the discharge end to locate the conveyor within operational reach of a further section of oil sand ore; excavating, sizing and transferring to the conveyor all ore in the further section within operational reach along the length of the conveyor; continuing to advance the conveyor about the discharge end to locate the conveyor within operational reach of additional sections of oil sand ore and after each advancement excavating, sizing and transferring the respective additional section of oil sand ore, until substantially all ore within an operational arc sector generally about the discharge end has been excavated, sized and transferred to the conveyor. 
         [0046]    In a further aspect the invention provides a method of extracting a body of oil sand ore for conveyance to a mobile slurry facility, the method comprising: locating the mobile slurry facility near a mine face of a body of oil sand ore; positioning a mobile conveyor within operational reach of a section of the ore body and locating a discharge end of the mobile conveyor to convey mined ore to the mobile slurry facility; extracting the section of the ore body and conveying it to the mobile slurry facility; advancing the mobile conveyor generally about the discharge end to locate the mobile conveyor within operational reach of a further section of the ore body; extracting the further section of the ore body and conveying it to the mobile slurry facility; continuing to advance the conveyor and convey additional sections of the ore body to the mobile slurry facility until the ore within an arc sector about the discharge end of the conveyor has been extracted. 
         [0047]    In a further aspect the invention provides a method of increasing the effective length of a mobile conveyor for conveying a mined ore, the method comprising:
       (a) Locating a mobile conveyor within operational reach of a section of ore;   (b) Extracting the section of ore within operational reach of the conveyor and transferring the extracted ore to the conveyor;   (c) Advancing the conveyor generally about the discharge end to locate the conveyor within operational reach of a further section of ore;   (d) Repeating steps (b) and (c) until substantially all ore within operational reach of the conveyor has been extracted. and,   (e) relocating the discharge end of the conveyor to a substantial center of the arc.       
 
         [0053]    In a further aspect the invention provides a method for increasing the mineable volume of ore capable of being transported from the mine site to a discharge point using a mobile conveyor, the method comprising: locating the mobile conveyor near a mine face with a discharge end located in communication with the discharge point; excavating a section of ore within operational reach of the mobile conveyor along the length of the conveyor; repeatedly advancing the mobile conveyor through an operational arc generally about the discharge end to locate and extract additional sections of ore within operational reach along the length of the conveyor; and, relocating the mobile conveyor to locate the discharge end in communication with a new discharge point located near the perimeter of the operational arc. 
         [0054]    In a further aspect the invention provides a process line for excavating and processing oil sands ore near a mine face, the process line comprising: a mobile excavator for excavating ore along the length of a mobile mining conveyor; a mobile comminutor for receiving and comminuting excavated ore and transferring comminuted ore to the mobile mining conveyor; the mobile mining conveyor conveying the comminuted ore to a transfer conveyor; the transfer conveyor conveying the comminuted ore to a mobile slurry facility; the mobile slurry facility converting the comminuted ore into a slurry and pumping and conditioning the slurry through a hydro-transport pipeline to a mobile extraction facility; the mobile extraction facility receiving the slurry and combining with a water stream to separate a bitumen stream and a tailings stream from the slurry; herein the bitumen stream is directed to a separation facility and the tailings stream is directed to a tailings treatment facility. 
         [0055]    In a further aspect the invention provides a process line for excavating and processing oil sands ore near a mine face, the process line comprising: a mobile excavator for excavating ore along the length of a mobile mining conveyor; a mobile comminutor for receiving and comminuting the excavated ore and transferring the comminuted ore to the mobile mining conveyor; the mobile mining conveyor conveying the comminuted ore to a transfer conveyor; the transfer conveyor conveying the comminuted ore to a mobile slurry facility; at the mobile slurry facility combining the comminuted ore with process water to produce a slurry and pumping and conditioning the slurry through a hydro-transport pipeline to a mobile extraction facility as a slurry feed; at the mobile extraction facility receiving the slurry feed and directing the slurry feed and a water stream as inputs to a three stage countercurrent cyclone separator; the cyclone separator producing a bitumen rich stream and a tailings stream; the bitumen rich stream being directed to a froth concentration unit; the froth concentration unit separating the bitumen rich stream into a bitumen product stream, a recycled water stream and a fine tailings stream; the fine tailings stream being combined with the tailings stream to produce a tailings product stream; the tailings product stream being directed to a tailings treatment facility; the tailings treatment facility receiving the tailings product and combining the tailings product with an additive to produce a treated tailings stream; the treated tailings stream being directed to a tailings pond; the treated tailings stream being separated into a dry tails phase and a water phase; and, the water phase being collected at the tailings pond and recycled as industrial process water. 
         [0056]      FIG. 1  is an illustration of the process overview of the present invention. The aim of the present invention is to provide a closed loop mining process that minimises the transport of the mineral component of the ore from the mine face and treats the tails to release the water component for reclamation as industrial process water. The process may be described as comprising the following main stages: 
         [0057]    excavating the ore  10 ; 
         [0058]    conveying the excavated ore to a slurry facility  12   
         [0059]    slurrying the comminuted ore  14 ; 
         [0060]    hydro-transporting the slurry to condition the slurry and transport it to an extraction facility  16 ; 
         [0061]    extracting from the slurry an enriched bitumen froth feed and a tailings feed  18 ; 
         [0062]    treating the tailings feed with an additive  20 ; 
         [0063]    depositing the treated tailings feed at a deposition site  22 ; and, 
         [0064]    recycling the reclaimed water as industrial process water  24 . 
         [0065]      FIG. 2  depicts the process line of the present invention comprising a mobile excavator  200  that excavates ore from a mine face  101  and transfers the excavated ore to a mobile comminutor  500 . The mobile comminutor  500  comminutes the ore to transportable size for delivery to a mobile mining conveyor  580 . The mobile mining conveyor  580  delivers the crushed ore to a mobile slurry facility  800  where the crushed ore is converted into a slurry with the addition of hot process water and further comminuting and screening. Optionally process agents or conditioning aids may be added to the slurry at the mobile slurry facility  800 . The slurry is pumped through a hydro-transport pipeline  850  to a mobile extraction facility  900  where the bitumen is separated from the mineral component. The separated bitumen is diverted to a secondary extraction facility  1500  while the mineral component is directed for tailings treatment  1100  prior to being deposited at a tailings deposition site  1150 . Tailings treatment  1100  preferably comprises the addition of an additive to the tailings to assist in separation of the water component of the tailings from the sand and fines. The treated tailings are then deposited at tailings deposition site  1150 . After separation of the water from the solid component of the tailings, the water may be collected at the tailings deposition site and recycled as industrial process water, either back into the process, for instance to be used in the slurry and extraction stages, or else directed for other industrial process water uses. 
         [0066]    The stages of the process will now be described in more detail. 
         [0067]    Referring to  FIG. 3 , a top view of the excavation portion of the present invention is shown. A mobile excavator  200 , for instance a shovel, removes ore from the ore body  100  at the mine face  101 . The mobile excavator  200  transfers the ore to a mobile comminutor  500  before it is transported to the mobile slurry facility  800 . The ore is deposited into the apron feed hopper  520  of the mobile comminutor  500  that feeds an apron feeder  530  to deliver the mined ore to primary comminuting rolls to comminute, or crush, the ore down to transportable size. The apron feed hopper  520  serves the dual purpose of receiving the excavated ore and acting as a “dry” surge or inventory of excavated ore by receiving buckets of excavated ore and delivering a steady stream of excavated ore to the primary comminuting rolls. The comminuted ore falls onto the discharge conveyor  550  for conveyance from the mobile comminutor  500  to a mobile mining conveyor hopper  570  for delivery to mobile mining conveyor  580 . The mobile mining conveyor  580  conveys the comminuted ore to a transfer conveyor that delivers the ore to the mobile slurry facility  800 . 
         [0068]    Referring to  FIG. 4 , a side view of the excavation portion of the present invention is shown. The mobile excavator  200  is within close proximity of an ore body  100  and within operational reach of a mine face  101 . The mobile excavator  200  excavates ore from the mine face  101 . Prior to transport, the excavated ore must be sized and screened for reject material such as metal. The mobile excavator  200  directs the excavated ore to the mobile comminutor  500  which comminutes and screens the ore. Generally, the mobile comminutor  500  preferably includes tracks  510 , an apron feeder hopper  520 , an apron feeder  530 , primary comminuting rolls  540  and a discharge conveyor  550 . Cable reels  575  transported by the mobile mining conveyor hopper  570 , supply power and communication cables to the excavator  200 , and mobile comminutor  500 . 
         [0069]      FIG. 5  is an illustration of the preferred embodiment of a mobile comminutor  500  according to the present invention. The ore is initially deposited by the excavator  200  into the apron feeder hopper  520  which directs the ore onto an apron feeder  530 . The apron feeder  530  conveys the ore to the primary comminuting rolls  540  which comminutes the ore down to a conveyable size typically limiting ore pieces to a diameter of approximately less than about 350 mm. The apron feeder  530  and primary comminuting rolls  540  also preferably includes at least two level detectors. The feeder level detector  532  is directed down the apron feeder  530  to detect large lumps of ore travelling up the apron feeder  530 . When a large lump is detected, the feeder level detector  532  alerts the apron feeder  530  to slow down, to allow the material to be processed by the primary comminuting rolls  540 . Similarly, sizing level detector  534  is directed across the primary comminuting rolls  540  to detect a build-up of material at the primary comminuting rolls  540 . If the level of ore begins to build up above the primary comminuting rolls  540 , the comminuting level detector  534  alerts the apron feeder  530  to slow down the delivery of ore to allow time for the primary comminuting rolls  540  to process the built up ore. Preferably the speed of the apron feeder  530  is also controlled by a weight sensor located on the discharge conveyor  550 . By controlling the speed of the apron feeder  530  using the level detectors and weight sensor, a steady supply of transportable sized ore may be provided to the mobile mining conveyor  580 . Optionally, heaters  522  may be provided at the hoppers and elsewhere as required to minimize build-up of ore when operating under extreme cold conditions. 
         [0070]    The mobile comminutor  500  preferably includes tracks  510  to permit relocation of the mobile comminutor as the excavator  200  works the ore body.  FIGS. 19   a  to  19   c  illustrate an embodiment where the mobile comminutor  500  relocates each time the excavator  200  relocates to work a section of the ore body. As illustrated in  FIGS. 19   a  to  19   c , the excavator  200  excavates all ore within its operational reach at a particular location, and then relocates closer to the newly exposed mine face  101 . As the excavator  200  relocates, the comminutor  500  and mobile mining conveyor hopper  570  also relocate to pace the excavator  200 . In the embodiment of  FIGS. 19   a  to  19   c  the mobile comminutor  500  takes multiple short relocation steps at the same time that the excavator is relocating. 
         [0071]      FIGS. 20   a  and  20   b  illustrate an alternate embodiment in which the excavator  200  excavates all ore within its operational reach at a particular location, and then relocates closer to the newly exposed mine face  101 , but remaining within operational reach of the mobile comminutor  500 . In this fashion, the excavator takes multiple relocation steps excavating about the mobile comminutor  500  location until all ore within operational reach of the mobile comminutor  500  has been excavated. Once the ore has been excavated, both the mobile comminutor  500  relocates to a new location closer to the newly exposed mine face  101 . In the embodiment of  FIGS. 20   a  and  20   b , the mobile comminutor  500  takes less relocation steps to access all ore within operational reach of the mobile mining conveyor  580 . The excavator  200  may, however, take additional relocation steps or face some periods of down time while waiting for the mobile comminutor  500  to relocate closer to the newly exposed mine face  101 . 
         [0072]    Optionally the mobile comminutor  500  includes supports  515  that are preferably lowered during operation while the excavator  200  is working a section of the ore body  100  to stabilise the mobile comminutor  500 . The supports  515  may preferably be raised to permit the mobile comminutor  500  to relocate when the excavator  200  moves to a new section of the ore body  100 . It will be appreciated that supports  515  may be replaced by additional tracks  510 , or dispensed with entirely, depending upon the weight distribution and stability of the mobile comminutor  500 . 
         [0073]    The sized ore is directed to a discharge conveyor  550  for delivery to the mobile mining conveyor  580 . Ore that is too large, or too hard to be crushed in the primary comminuting rolls  540 , is directed to a reject door and discharged out the reject chute to the ground below the mobile comminutor  500 . Preferably the ore is also screened at the mobile comminutor  500  for metal contaminant, such as excavator teeth. As will be appreciated, other methods of screening the ore for metal and discarding metal are possible, such as screening the ore downstream after conveyance by the mobile mining conveyor  580 . Most preferably, however, the mobile comminutor  500  includes a metal detector  552  to examine the sized ore on the discharge conveyor  550  for metal contaminants. If metal is detected by metal detector  552 , the apron feeder  530  and discharge conveyor  550  may be temporarily halted and a reject chute in the mobile mining conveyor hopper  570  may be aligned under the discharge point of the discharge conveyor  550 . The discharge conveyor  550  then advances until the metal is discarded off the discharge conveyor  550  and into the reject chute. The discharge conveyor  550  is then temporarily halted again while the mobile mining conveyor hopper  570  is re-aligned to direct discharged ore to the mobile mining conveyor  580 . 
         [0074]    Referring to  FIG. 6 , the sized ore is first delivered to a mobile mining conveyor hopper  570  by the discharge conveyor  550 . The mobile mining conveyor hopper  570  preferably traverses along rails or tracks that run the length of the mobile mining conveyor  580 . As the excavator  200  advances along the mine face, the mobile comminutor  500  follows the progress of the excavator. The mobile mining conveyor hopper  570  traverses along the transfer conveyor  580  to receive the crushed ore from the discharge conveyor  550  and deliver it to the mobile mining conveyor  580  for conveyance. Preferably, the mobile mining conveyor hopper  570  conveniently includes cable reels  575  to spool out power and communication cables to the mobile comminutor  500  and excavator  200  as they traverse along the mine face  101 . In this manner, the power generation or transmission connection may be conveniently located at the discharge end  590 , of the mobile mining conveyor  580 , minimizing the need to move such equipment. The mobile mining conveyor  580  also preferably comprises crawler tracks  600  distributed along the length of the conveyor which enables the mobile mining conveyor  580  to advance laterally or to advance about and end of the mobile mining conveyor  580 . Optionally, the mobile mining conveyor  580  may be accompanied by a fluid trailer  585  that supplies water or glycol to be sprayed on the transfer conveyor  580  belt to prevent material from sticking to the belt in extreme weather conditions. 
         [0075]    In a preferred embodiment the mobile mining conveyor  580  is comprised of multiple conveyor sections that are connected together to create a chain of conveyor sections that collectively comprise the mobile mining conveyor  580 . A continuous belt is supported by the sections to convey ore to the discharge end of the mobile mining conveyor  580 . Preferably, each section includes at least one crawler track  600  to reposition that section. More preferably the crawler tracks  600  are provided with independent height adjustable supports connecting the crawler tracks  600  to the mobile mining conveyor  580 . In a preferred embodiment the sections are joined by pivot joints and an alignment gauge  585 , such as string pots, is used to determine whether a section is inline with its adjacent sections. If the section is not inline, the section&#39;s crawler track  600  is repositioned until the section is inline and horizontal. In this way, the mobile mining conveyor  580  may be advanced generally about the discharge end  590  by manually advancing the free end to a desired location. With the advancement of the free end crawler track, the adjacent section will no longer be inline with the end section. Upon detecting mislevel or misalignment, the adjacent section crawler track is also repositioned to maintain level alignment with the end section. Similarly, the next section in the chain detects a misalignment with the adjacent section and its crawler track is repositioned to maintain level alignment. In this way the mobile mining conveyor  580  may be advanced about the discharge end  590  by manually advancing the free end crawler until it is in operational proximity to the current mine face  101 . Alternatively the crawler tracks  600  may be controlled by a central motion controller to co-ordinate the advancement of all crawler tracks  600 . 
         [0076]    One advantage of employing a mobile mining conveyor  580 , over a relocatable conveyor, is that material that spills over the sides of the mobile conveyor does not significantly accumulate in a particular location. Depending upon the duration of operation the amount of spilled material that may accumulate around a relocatable conveyor may be considerable. By mining with a mobile mining conveyor  580 , the process avoids the need to clear spilled material prior to relocating the conveyor. 
         [0077]    Referring to  FIGS. 7 and 8 , at the discharge end  590  of the mobile mining conveyor  580 , the sized ore is deposited into a transfer conveyor hopper  610  that feeds the sized ore onto a transfer conveyor  620  that transports the material to the feed chute of a mobile slurry facility  800 . 
         [0078]    The mobile mining conveyor  580  conveys sized ore along its length to the discharge end  590 . The discharge end  590  is in communication with a discharge point such that as sized ore is discharged off the discharge end  590 , it continues in a projectile motion to the discharge point a short distance from the discharge end  590 . In operation the mobile mining conveyor  580  is positioned such that the discharge point of the mobile mining conveyor is aligned with a target, in this case approximately the center of the transfer conveyor hopper  610 . Preferably a location sensor is included to assist in locating the discharge point of the mobile mining conveyor  580  central to the transfer conveyor hopper  610 , and maintaining its alignment with respect to transfer conveyor hopper  610 , while advancing the mobile mining conveyor  580  about the discharge end  590 . 
         [0079]    According to a preferred embodiment of the present invention, the mobile mining conveyor  580  consists of multiple independent sections. One of the advantages of the preferred embodiment is that each section may be individually powered and operated depending upon the location of the mobile mining conveyor hopper  570 . Similarly, since each section is independently mobile, each section may be replaced as necessary if it breaks down while in service. Alternatively, a section may be removed from the mobile mining conveyor  580  and operation may continue, albeit with a mining conveyor of shorter length. Preferably the conveyor belt is a continuous belt as known in the art. Conveyor sections may be added or removed by adding or removing sections of the belt to accommodate the change in the length of the conveyor. 
         [0080]    In a preferred embodiment the location sensor is optical sensor  595  located at the discharge end  590  that monitors the location of a positioning ring  605  located around the transfer conveyor hopper  610 . As the mobile mining conveyor  580  is advanced about the transfer conveyor hopper  610 , the optical sensor  595  monitors the location of the positioning ring  605  and provides feedback to control the advancement of the tracks  600  on the discharge conveyor section  597  so as to maintain the discharge point in the transfer conveyor hopper  610 . Since the discharge end  590  is located with reference to the transfer conveyor hopper  610 , the geometry of the transfer conveyor hopper  610  may effect the path through which the discharge end  590 , and hence the mobile mining conveyor  580 , may travel. For instance, the transfer conveyor hopper  610  may be circular in which case the discharge end  590  will travel in a generally circular fashion. Alternatively, the transfer conveyor hopper  610  may be elongate in which case the discharge end  590  may travel in a generally arcuate fashion. 
         [0081]    As described above, the mobile mining conveyor  580  conveys the sized ore off the discharge end  590  to a discharge point aligned with the transfer conveyor hopper  610  of a transfer conveyor  620  for delivery to the mobile slurry facility  800  where it is converted into a slurry and pumped into pipe-line  850  for transport to a de-sanding facility en route to a bitumen upgrader facility. Since the mobile mining conveyor  580  advances about the transfer conveyor hopper  610 , the transfer conveyor  620  may remain stationary throughout the execution of an operational arc. Preferably the transfer conveyor  620  is provided with a platform  630  on its underside for engaging a crawler when the transfer conveyor  620  is to be repositioned. In this embodiment it is unnecessary to include a motive drive on the transfer conveyor  620  since it remains stationary for extended periods of time. 
         [0082]    Referring to  FIGS. 9   a - 9   b , preparation of an ore body according to a preferred embodiment of the present invention is presented. Preferably, the ore body is prepared by initially excavating a “pocket”  55  into the mine face  101  with the excavator  200  and mobile comminutor  500  to remove all of the ore within operational reach of the excavator  200  and mobile comminutor  500  while a discharge point off the discharge conveyor  550  is located outside the pocket  55  being excavated. The purpose of excavating the pocket  55  is to permit location of the mobile slurry facility  800  as close as possible to the mine face to facilitate removing the greatest possible volume of ore while the mobile slurry facility  800  remains in a single location. While it is possible to operate the excavator  200  and mobile comminutor  500  further into the ore body beyond the operational reach of the excavator  200  and mobile comminutor  500 , limiting excavation to their operational reach with the discharge point being located outside the pocket  55  minimises the need to employ additional equipment to transport the ore clear of the pocket  55 . 
         [0083]    As illustrated in  FIG. 9   c , after excavation of the initial pocket, the mobile slurry facility  800  and transfer conveyor  620  may be positioned such that the transfer conveyor hopper  610  is located in the pocket, thus locating the mobile slurry facility  800  at an optimal location for removing a maximum volume of ore before having to move the mobile slurry facility  800 . Optionally, as illustrated in  FIG. 9   c , the excavator  200  and mobile comminutor  500  may continue to work the ore body to enlarge the pocket  55  without the mobile mining conveyor  580  by locating a discharge point off the discharge conveyor  550  in the apron feed hopper  610 . An additional volume of the ore body is within operational reach of the excavator  200  and mobile comminutor  500  when the discharge point is located in the transfer conveyor hopper  610  within the pocket  55 . The advantage of excavating an enlarged pocket by delivering the ore directly from the mobile comminutor  500  to the transfer conveyor hopper  610  is that it consumes less energy and results in less wear and tear on equipment. Optionally, the ore excavated during the initial pocket excavation, illustrated in  FIGS. 9   a - 9   b , may be fed into the mobile slurry facility  800  at this time by depositing the ore in the transfer conveyor hopper  610 . Alternatively, the initially excavated ore may be retained as a dry surge to feed to the mobile slurry facility during excavation down time such as excavator shovel repairs or conveyor maintenance. 
         [0084]    Referring to  FIGS. 10   a - 10   e  a top view schematic of the process of the present invention is presented.  FIG. 10   a  illustrates a close-up top view of a mining cell according to an embodiment of the present invention with the ore body  100  and the mobile mining conveyor  580  in an initial position. The excavator  200  removes ore from a mine face  101  and delivers it to a mobile comminutor  500  by depositing it in the apron feed hopper  520  to be directed to an apron feeder  530 . The apron feeder  530  carries the ore to primary comminuting rolls  540 , not shown in this view, for crushing before the ore is directed to the discharge conveyor  550  to be transferred to the mobile mining conveyor hopper  570  to direct the ore to the mobile mining conveyor  580  for delivery off the discharge end  590  of the mobile mining conveyor  580  to a discharge point. Preferably, the mobile mining conveyor  580  is oriented to position the discharge point in a transfer conveyor hopper  610 . Most preferably the mobile mining conveyor  580  positions the discharge point at or near the center of the transfer conveyor hopper  610 . The transfer conveyor hopper  610  supplies the conveyable ore to a transfer conveyor  620  that delivers the ore to a mobile slurry facility  800 . The mobile slurry facility  800  adds HPW to convert the ore into a slurry that is pumped into a pipe-line  850  for hydro-transport. 
         [0085]      FIG. 10   b  illustrates the mining cell in a top view with the ore body  100  to be excavated and the excavator  200 , mobile comminutor  500  and mobile mining conveyor hopper  570  starting at an end of the mobile mining conveyor  580  and removing ore within operational reach along the length of the mobile mining conveyor  580 . 
         [0086]      FIG. 10   c  illustrates the mining cell in a top view after all the ore within operational reach of the mobile mining conveyor  580  in the first position has been excavated and the conveyor has been advanced about the discharge end  590  to position a further section of ore within operational reach of the mobile mining conveyor  580  while locating the discharge point in the transfer conveyor hopper  610 . As illustrated, once the mobile mining conveyor  580  has been advanced, the excavator  200 , mobile comminutor  500  and mobile mining conveyor hopper  570  move along the mobile conveyor  580  and excavate the ore within operational reach of the mobile mining conveyor  580 . After all the ore within operational reach of the mobile mining conveyor  580  has been excavated, the mobile mining conveyor  580  is again advanced about the discharge end. 
         [0087]      FIG. 10   d  illustrates the mining cell in a top view with the ore body  100  and the mobile mining conveyor  80  having been advanced to a further position and the excavator  200 , mobile comminutor  500  and mobile mining conveyor hopper  570  having completed excavating all the ore within operational reach of the mobile mining conveyor  580  in the further position. 
         [0088]      FIG. 10   d  illustrates the mining cell in a top view with the ore body  100  and the mobile mining conveyor  80  having been advanced to a further position and the excavator  200 , mobile comminutor  500  and mobile mining conveyor hopper  570  having completed excavating all the ore within operational reach of the mobile mining conveyor  580  in the further position. 
         [0089]      FIG. 10   e  illustrates the mining cell in a top view with the ore body  100  and mobile mining conveyor  80  having been advanced through an operational arc about the discharge end and the excavator  200  and mobile comminutor  500  having excavated, comminuted and transferred to the mobile mining conveyor hopper  570  an operational arc sector of ore. 
         [0090]      FIG. 10   f  illustrates the mining cell in a top view with the ore body  100  after the excavator  200  and mobile comminutor  500  have prepared an initial pocket at the perimeter of the excavated arc sector. The mobile slurry facility  800  has been moved from its prior location to be in close proximity to the mine face  101  with the transfer conveyor  620  located in the pocket. The excavator  200  and mobile comminutor  500  are initiating excavation of an enlarged pocket about the transfer conveyor hopper  610 . The mobile mining conveyor  580  has been positioned in close proximity to the mobile slurry facility  800  and transfer conveyor  620  to begin operation after the excavator  200  and mobile comminutor  500  have completed the enlarged pocket. 
         [0091]      FIG. 11  illustrates the mining cell in a top view with the ore body  100  after the mobile mining conveyor  580  has been advanced through an operational arc sector about a mobile slurry facility  800 . In comparison to the embodiment illustrated, a conventional fixed conveyor  575  of similar length is illustrated with the operational reach of the conventional fixed conveyor  575  illustrated with cross-hatching  585 . As will be appreciated the effective length of the mobile mining conveyor  580  is greater than that of a conventional fixed conveyor  575  since a greater volume of ore may be excavated before relocating the mobile slurry facility  800  with a mobile mining conveyor  580  according to the present invention. 
         [0092]    As described above, the discharge end  590  of the mobile mining conveyor hopper  580  delivers conveyable ore to the transfer conveyor hopper  610  of the transfer conveyor  620 . The transfer conveyor  620  supplies the conveyable ore to the mobile slurry facility  800 . Since the mobile slurry facility  800  preferably utilises gravity to assist in slurrying the ore, the transfer conveyor  620  serves to elevate the conveyable ore to the height of the mobile slurry facility  800  ore input chute. The use of a transfer conveyor  620  to offset the mobile slurry facility  800  from the discharge end  590  also provides the opportunity to increase the operational arc of the mobile mining conveyor hopper  580 . Furthermore, a single mobile slurry facility  800  may be used to process ore from multiple mobile mining conveyors  580 . In such an embodiment, the transfer conveyor  620  may be longer than the minimum length required for supplying conveyable ore to a mobile slurry facility  800  fed by a single mobile mining conveyor  580 . 
         [0093]      FIG. 18   a  is an illustration of a mobile mining conveyor  580  combined with an extended transfer conveyor  623  feeding the transfer conveyor  620 . The embodiment of  FIG. 18   a  allows a mobile mining conveyor  580  to access a greater volume of ore before the mobile slurry facility  800  requires relocation. An additional feature of traversing the mobile mining conveyor  580  along the extended transfer conveyor  623  before rotating the mobile mining conveyor  580  about the distal end  623   b  of the extended transfer conveyor  623 , is that it provides access to a section of ore body having straight sides. Among other uses, such an arrangement may be useful to access a volume of ore from a given mobile slurry facility  800  location when the ore body is of a relatively narrow width. The extended transfer conveyor  623  allows a larger volume of ore to be accessed than would otherwise be the case for the mobile mining conveyor  580  of a given length. 
         [0094]      FIG. 18   b  illustrates an embodiment where a single mobile slurry facility  800  may be used to process ore from multiple mobile mining conveyors  580   a ,  580   b . In the embodiment illustrated, two mobile mining conveyors  580   a ,  580   b  access adjacent volumes of ore. Each of the discharge ends  590   a ,  590   b  pivot about a separate discharge point for transferring ore to conveyors  625   a ,  625   b  that convey the mined ore to their discharge ends  592   a ,  592   b  to feed transfer conveyor  620 . The discharge points may be fixed at a point along the conveyors  625   a ,  625   b , as illustrated in  FIG. 18   b , or alternatively as illustrated in  FIG. 18   f , mobile conveyor hoppers may be used to allow the discharge points to traverse along the conveyors  625   a ,  625   b . After the mobile mining conveyors  580   a ,  580   b  have completed an arc sector as suggested in  FIG. 18   b , one of the mobile mining conveyors  580   a ,  580   b  may be positioned to pivot about a discharge end  592   c  located at the transfer conveyor  620  to remove a further section of ore between the arc sectors illustrated within reach of the mobile mining conveyors  580   a ,  580   b . The embodiment of  FIG. 18   b  allows for a large volume of ore to be processed with a single mobile slurry facility  800  at a location, increasing the time between moves for a given length of mobile mining conveyors  580   a ,  580   b . The embodiment may be implemented in a variety of methods, including operating both mobile mining conveyors  580   a ,  580   b  simultaneously, to feed twice as much ore to the mobile slurry facility  800 , or alternately operating each conveyor to ensure a steady feed of ore, for instance when one conveyor is inoperative, such as when equipment is moving or a shift change occurs. 
         [0095]      FIGS. 18   c  and  18   d  are plan view schematics, illustrating an embodiment where multiple mobile mining conveyors  580 ,  581  are deployed in series. The conveyors  580 ,  581  may be of similar length, or may comprise different lengths as is convenient for excavating a particular ore body  100 . The excavator  200  and mobile comminutor  500  work the ore body  100  feeding mobile mining conveyor hopper  571 . The use of multiple mobile mining conveyors  580 ,  581  allows for efficient mining of an ore body, including avoiding low yield volumes  105  (shown in plan views as an area). As illustrated in  FIG. 18   c , the mobile mining conveyor  580  may be deployed as a face conveyor to allow mobile mining conveyor  581  to pivot about the mobile mining conveyor hopper  570  to access ore around the low yield volume  105 .  FIG. 18   d  illustrates an embodiment where the mobile mining conveyor  580  is pivoting about the transfer conveyor  620 , and the mobile mining conveyor  581  is pivoting about the mobile mining conveyor hopper  570 . In an embodiment, mobile mining conveyor  581  may be advanced through all of the ore within operational reach of the mobile mining conveyor hopper  570  as it traverses along the mobile mining conveyor  580  which is held in a fixed position for the duration of the advancement. Alternatively, the mobile mining conveyors may both be advanced by pivoting about the transfer conveyor  620  providing an effective mobile conveyor length a length equivalent to the combined lengths the mobile mining conveyors  580 ,  581 . 
         [0096]      FIG. 18   e  illustrates an embodiment where multiple mobile mining conveyors  580 ,  581  are deployed to excavate ore along mine wall limit  102 . As illustrated, the conveyors  580 ,  581  may be of differing lengths as required to efficiently mine the wall limit  102 . 
         [0097]      FIG. 18   f  illustrates an embodiment where multiple conveyors are working an ore body  100  around low yield sections  105 . In the embodiment illustrated, the mobile mining conveyors  580   a  and  580   b  are of differing length to better work between low yield sections  105 . Mobile conveyor hoppers  570  traverse along conveyors  625   a ,  625   b  to allow access to minable ore in the ore body  100  and avoid the low yield sections  105 . 
         [0098]    A mobile slurry facility  800  converts the conveyable ore delivered by the transfer conveyor  620  into a slurry for hydro-transport. In a preferred embodiment of the mobile slurry facility  800  the conveyable ore is first discharged from the transfer conveyor  620  into the roller screen feed chute  720 . The roller screen feed chute  720  feeds the roller screen  740  to crush the ore to a convenient size for slurrying (typically less than 65 mm in diameter) and allow the crushed and sized ore to fall through the screen. Oversize material that does not fall through the roller screen  740  passes to an oversize comminutor  760  that crushes the lumps of oversize down to acceptable size. Hot Process Water (HPW) is typically introduced at the roller screen feed chute  720  and additional HPW is added directly over the roller screen  740  and oversize comminutor  760 . The additional HPW assists in processing the ore, preventing ore buildup and defining the slurry density. The majority of the wet sized ore passes directly through the roller screen  740  for conversion to slurry in the slurry pump box  780 . The remaining oversize is wetted and crushed by the oversize comminutor  760  before falling into the slurry pump box  780  for conversion to slurry. While it is possible to provide for an overflow chute to discard oversize, it is preferable to size the roller screen  740  and oversize comminutor such that they are capable of processing all of the ore supplied by the transfer conveyor  620 . 
         [0099]    Typically, HPW will be proportionately distributed approximately 70% at the roller screen feed chute  720 , 20% at the roller screen  740  and 10% at the oversize comminutor  760 . Where the invention includes a metal detector and reject ore discharge mechanism at the mobile comminutor  500 , all of the ore received by the mobile slurry facility  800  may be processed using the roller screen  740  and oversize comminutor  760 . While it is possible to detect metal in the ore at the roller screen  740 , it is preferable to discard reject material as soon as possible in the process. Furthermore, it is preferable to discard reject material prior to processing by the primary comminuting rolls  540 . One advantage of the combination of the mobile comminutor  500  and mobile slurry facility  800  of the present invention is that reject material is discarded near the location of excavation. As the excavator  200  works an ore body, detected reject material will be discarded near the location of its excavation. Not only does this avoid transporting reject material along the mobile mining conveyor  580  where it can damage equipment but it eliminates the need for reject material handling equipment at the mobile slurry facility  800  where it would be much more difficult to incorporate such equipment. 
         [0100]    The sized ore and HPW falls into the slurry pump box  780  that is sized for a slurry retention time of approximately one minute. The slurry pump box  780  supplies the hydro-transport pump  820  with slurry. A one minute retention time is the preferred minimum to provide a wet surge capability to continuously supply slurry to the pump. When the level of slurry falls below a low level, Cold Process Water (CPW) may be added to maintain the level in the slurry pump box and ensure the hydro-transport pump  820  does not cavitate. As required, HPW may be added along with CPW to maintain a working temperature under cold conditions. 
         [0101]    Emergency ponds are preferably located near the mobile slurry facility  800  to allow dumping of slurry from the mobile slurry facility  800  or the pipeline  850  under emergency conditions. The size of the emergency ponds is preferably large enough to accommodate the directed drainage of the contained volume of any one of the following: a drainable section of hydro-transport pipeline (24″), a drainable section of HPW pipeline (24″), a drainable section of CPW pipeline (20″), or the volume of the slurry pump box  780 . The size of the drainable sections of the pipelines are site specific due to logistical and geographical features. The emergency pond is preferably serviced by a submersible pump which is able to return the pond fluids back to the process through the slurry pump box at the end of the emergency. 
         [0102]    The slurry is pumped through the hydro-transport pipeline  850  to an extraction facility. As mentioned above, in addition to transporting the slurry, the hydro-transport process serves the secondary purpose of conditioning the slurry. The length of hydro-transport required to condition the slurry depends on several factors including the grade of ore, temperature of the ore, temperature of the process water and the size of ore being delivered to the slurry pump box. Typically, to be fully conditioned the slurry requires at minimal distance of one kilometre of hydro-transport distance. 
         [0103]    Preferably the extraction facility is a mobile extraction facility  900  that receives as inputs the conditioned slurry as an ore slurry feed  1200  and process water  1205 , and produces as outputs an enriched bitumen stream  1400  and a tailings stream  1450 . In a preferred embodiment, the mobile extraction facility  900  comprises separate portable modules that may be transported to a location separately and then connected together in series to provide a single extraction facility. Preferably the mobile extraction facility  900  comprises a primary separation facility connected to a froth concentration facility. More preferably, the primary separation facility comprises two or more separate separation cyclone modules that are combinable in situ to comprise the primary separation facility. Most preferably, the primary separation facility comprises three separate separation cyclone modules connected in series in a countercurrent configuration. The use of separate modules allows for ease of portability and allows the process to be flexible to tailor the extraction facility to the ore body being excavated. For instance, a high grade ore body that contains very little fine solids/mineral component may not require the rigor of a three cyclone circuit, and in such a case the extraction facility may comprise only one or two of the modules. Generally, to accommodate all ore types, a three cyclone system is preferred. The modules preferably comprise transportable platforms, such as skids, that may be transported by crawlers or other motive modules. Alternatively, the modules may be provided with driven tracks. 
         [0104]    In an alternate embodiment, the mobile extraction facility  900  comprises a single facility, containing all separation vessels and primary froth concentration equipment. 
         [0105]    Use of a three stage cyclonic system is further advantageous in a mobile extraction system for several reasons. First, the size of each individual cyclone stage may be reduced since a three stage counter—current process results in a separation efficiency either equivalent to, or better than, current extraction methods. Second, each of the three cyclones may be transported separately, greatly improving the ease of relocating the extraction facility. Third, the use of a three stage countercurrent cyclonic system allows a mobile extraction facility to operate with a variety of ore grades. Fourth, as mentioned above, the number of stages may be tailored to match the separation efficiency with the grade of ore being processed. 
         [0106]    As described above, the slurry that is fed to mobile extraction facility  900  is generally formed using HPW. In conventional bitumen extraction equipment such as primary separation vessels (PSV), where bubble attachment and flotation are used for bitumen extraction, temperature can affect the efficiency of the extraction process. In the preferred extraction embodiments described above, the extraction process is not as temperature sensitive since the cyclone equipment provides solid/liquid separation based on rotational effects and gravity. Extraction efficiency tends to be maintained even as temperature drops making the cyclone extraction process more amendable to lower temperature extraction. This has energy saving implications at the mobile extraction facility  900  where water feed  1305  or recycled water stream  1370  do not have to be heated to the same extent as would otherwise be necessary to maintain a higher process temperature. 
         [0107]    Preferably each of the cyclone separation modules are self-contained and include a cyclone, as well as associated connections, pump boxes, and pumps. This way, if one unit has a mechanical failure, the extraction facility may be brought back online by simply replacing the faulty cyclone separation unit. Preferably the cyclone separation modules are connected in series in a countercurrent configuration in which the water stream and slurry stream enter at opposite ends of the three cyclone combination. Thus, for example, water entering the process (either make-up, recycled, or both) is first contacted with a bitumen-lean feed at the last cyclone separation unit in the series. The cyclonic separation units are preferably vertical cyclones, which have a reduced footprint. Suitable cyclonic separation vessels include those manufactured by Krebs Engineers (www.krebs.com) under the trade-mark gMAX. 
         [0108]    This modular arrangement of the extraction system provides for both mobility of the system and flexibility in efficiently handling of different volumes of ore slurry. For example, as illustrated in  FIG. 17 , a preferred setup according to an aspect of the invention in which each cyclone separation stage  106 ,  108  and  110  is mounted on its own independent skid  160  to form a mobile module. Positioned between each cyclone separation stage skid  160  is a separate pump skid  162  which provides appropriate pumping power and lines to move the froth streams and solid tailings streams between the cyclone separation stages. It is also possible that any pumping equipment or other ancillary equipment can be accommodated on skid  160  with the cyclone separation stage. In the illustrated arrangement of  FIG. 17 , groups of three mobile modules are combinable together to form cyclone separation facilities  102 ,  102 ′,  102 ″ to  102   n  as needed. Also associated with each cyclone separation facility is a mobile froth concentration facility  130  mobile modules comprising skids or other movable platforms with appropriate cyclone stage or froth concentration equipment on board may be assembled as needed to create additional mobile extraction systems  200 ′,  200 ″ to  200   n  to deal with increasing ore slurry flows provided by hydro-transport line  850 . Ore slurry from the transport line  850  is fed to a manifold  103  which distributes the slurry to a series of master control valves  165 . Control valves  165  control the flow of ore slurry to each mobile extraction system  200  to  200   n . This arrangement also permits extraction systems to be readily taken off-line for maintenance by switching flow temporarily to other systems. 
         [0109]    According to a preferred embodiment, the cyclone separation units  1210 ,  1220 ,  1230  are connected as illustrated in  FIG. 12 . The slurry is delivered by the hydro-transport pipeline  850  as an ore slurry feed  1200  to the first cyclone separation unit  1210 . The first cyclone  1210  separates the ore slurry feed  1200  into a first bitumen froth stream  1300  and first tailings stream  1310 . The first tailings stream  1310  is pumped to a feed stream of a second cyclone  1220 . The second cyclone  1220  produces a second bitumen froth stream  1320  and a second tailings stream  1330 . The second bitumen froth stream  1320  is combined with the ore slurry feed  1200  as the feed stream of the first cyclone  1210 . The second tailings stream  1330  is combined with a water feed  1305  as the feed stream of a third cyclone  1230 . The third cyclone  1230  produces a third bitumen froth stream  1340  and a third tailings stream  1350 . The third bitumen froth stream  1340  is combined with the first tailings stream  1310  as the feed stream of the second cyclone  1220 . The third tailings stream  1350  from the third cyclone  1230  forms a tailings stream  1400  that is pumped to a tailings treatment facility  1100 . 
         [0110]    Optionally a “scalping” unit  1205 , such as a pump box or the like, may be included on the ore slurry feed  1200  to remove any froth formed in the slurry feed  1200  during the hydro-transport process and divert the bitumen froth directly to be combined with the first bitumen froth stream  1300 . Removal of the bitumen rich froth at the scalping unit  1205  assists in further increasing the recovery efficiency of the primary separation facility. Preferably, as indicated, the scalping unit  1205  is located upstream of the infeed of the second bitumen froth stream  1320 . 
         [0111]    The first bitumen froth stream  1300  is directed to a froth concentration facility to reduce the water content, remove remaining fines, and produce an enriched bitumen product stream  1400 . Preferably, the froth concentration facility is located proximate to the primary separation facility. Most preferably, the froth concentration facility comprises a separate portable unit that may be combined with the primary separation facility units to comprise the mobile extraction facility  900 . Typically the froth concentration facility comprises at least a froth concentration vessel  1240 , such as a flotation column, a horizontal decanter, an inclined plate separator, or other similar device or system known to be effective at concentrating bitumen froth. In addition to the first bitumen froth feed, an air feed  1355  or chemical additive stream may also be introduced into the froth concentration vessel  1240 . Optionally the froth concentration facility may comprise a combination of effective devices. In a preferred embodiment, as illustrated in  FIG. 12 , the froth concentration vessel  1240  comprises a flotation column. In a further preferred embodiment for a mobile extraction facility a horizontal decanter is used to separate an enriched bitumen stream from the first bitumen froth stream. The selection of a series of countercurrent cyclone separators results in a compact separation facility that remains able to remove the majority of the mineral component from the ore slurry feed  1200 . The low solids content of the first bitumen froth stream permits the use of a horizontal decantor as the froth concentration vessel with a low risk of plugging due to sedimentation. Use of a horizontal decantor is desirable due to its small footprint, thus allowing for the potential of the vessel being made movable, and still result in a robust extraction facility that has a low propensity of being fouled with silt or other mineral component. 
         [0112]    Within the froth concentration vessel  1240 , the froth is concentrated resulting in an enriched bitumen froth product stream  1400 , that may optionally be transported to a secondary separation facility (not shown) to increase the hydrocarbon concentration in the froth before being pumped to an upgrader facility. Typically, the secondary separation facility will be a larger, more permanent facility. One advantage of the process of the present invention is that an enriched bitumen froth stream  1400  is produced relatively close to the excavation site, greatly reducing the current requirement to transport large volumes of water and mineral component to the permanent separation facility. 
         [0113]    Froth concentration vessel  1240  also produces a fine tailings stream  1360  that comprises water and fine solids contained in the first bitumen froth stream  1300 . In one embodiment, any known chemical additives may also be used in the froth concentration facility to enhance the separation of fines from the water. 
         [0114]    Preferably the fine tailings stream  1360  is diverted to a water recovery unit  1250 , which separates the fine tailings stream  1360  into a recycled water stream  1370  and a fine tailings stream  1380 . In a preferred embodiment, the water recovery unit  1250  is a hydrocyclone to separate small sized particulate since the majority of the mineral component is removed by the primary separation facility. The fine tailings stream  1380  is preferably combined with the third tailings stream  1350  to produce a tailings stream  1450  from the mobile extraction facility  900 . The recycled water stream  1370  is preferably combined with the water feed  1305  for input to the third cyclone. As necessary, the recycled water stream  1370  may also be combined with the third tailings stream  1350 , fine tailings stream  1380  or tailings stream  1450  as necessary to control the water content of the streams. Preferably density meters (not shown) monitor the streams to determine whether, and how much, recycled water  1370  should be added. The addition of water to the third tailings stream  1350  and tailings stream  1450  may be necessary to maintain a pumpable stream, as the primary separation facility removes most of the water from the third tailings stream  1350  and fine tailings stream  1380 . The water recovery unit  1250  provides significant efficiencies in that the process water used in the mobile extraction facility  900  is preferably heated. The recycled water stream  1370  is typically warm or hot, so that reintroducing the recycled water stream  1370  reduces the heat lost in the extraction process. 
         [0115]    An advantage of this preferred embodiment of the present invention is that water may be recycled in the extraction process, and the mobile extraction facility  900  produces a single tailings stream  1450 . 
         [0116]    In a further optional embodiment, the ore slurry feed  1200  may be provided with any number of known additives such as frothing agents and the like prior to being fed to the primary separation facility to prepare the ore slurry feed  1200  for extraction. An example of such additives would be caustic soda, geosol, or other additives as described in U.S. Pat. No. 5,316,664. 
         [0117]    As mentioned above, the tailings stream  1450  is pumped to a tailings treatment facility  1100 . The tailings treatment facility  1100  may be located at the mobile extraction facility  900 , or some distance from the mobile extraction facility  900  depending upon the availability of a tailings deposition site  1150 . As will be appreciated, the location of the tailings deposition site  1150  is preferably close to the mobile extraction facility  900  to minimize the distance the tailings stream  1450  must be transported. However, the tailings treatment facility  1100  may be located distant from the mobile extraction facility  900  if it is necessary to locate the tailings deposition site  1150  at a distant location. 
         [0118]    While the tailings treatment facility  1100  may comprise a known method or process of handling tailings, preferably tailings treatment facility  1100  comprises the addition of a rheology modifier or other such additive to the tailings stream  1450  prior to deposition at the tailings deposition site. An example of a suitable additive is described in PCT publication WO/2004/969819 to Ciba Specialty Chemicals Water Treatment Limited. 
         [0119]    In a further preferred embodiment, the third tailings stream  1350  and fine tailings stream  1380  are mixed to ensure a homogenous distribution of coarse and fine particulate in the tailings stream  1450 . A preferred additive is a rheology modifier additive such as a water soluble polymer that may be added and mixed with the tailings stream  1450  to produce a treated tailings stream. The additive may be mixed into the tailings stream  1450  either during a pumping stage, or subsequently added in liquid form near the tailings deposition site. Preferably the treated tailings are deposited at the tailings deposition site and allowed to stand and rigidify thereby forming a stack of rigidified material. The addition of the additive results in a whole dry tails that rigidities relatively quickly to produce a relatively homogenous tailings deposition. After application of the additive, the water separates from the mineral component free from the fines. Unlike conventional tailings ponds, after addition of the additive the treated tailings produced according to the present invention releases water that is sufficiently clear to be recycled as industrial process water almost immediately after tailings deposition. Furthermore, the recycled industrial process water is often still warm, reducing the energy required to be added to produce hot process water. The industrial process water may be recycled back into the mobile extraction facility  900 , the mobile slurry facility  800  or other industrial processes as required. Furthermore, after separation of the water, the mineral component is comprised of both sand and fines, and is thus more stable than typical tailings produced by known processes. This provides the unique opportunity to reclaim the solid tailings relatively soon after excavation. 
         [0120]    A suitable mobile slurry facility may comprise the slurry apparatus  10  illustrated in  FIGS. 13 to 16  and further described in applicant&#39;s co-pending application METHOD AND APPARATUS FOR CREATING A SLURRY, filed Nov. 9, 2006 and claiming priority from CA2,526,336. 
         [0121]    As shown in  FIG. 13 , the slurry apparatus  10  provides a frame  20  having a base  22 . The frame  20  may optionally also be provided with sides  24 . The frame  20  is preferably formed from steel girders or I-beams having the required load-bearing capacity, welded, bolted, or otherwise suitably affixed together. The frame supports a slurry box  30 , which may be a conventional slurry box constructed to support the desired slurry load. The slurry box  30  essentially acts as a wet surge, maintaining the required constant supply of slurry to the slurry pump  39 . The slurry box  30  provides a slurry outlet  38  which feeds the slurry pump  39 , and the slurry pump  39  in turn provides a slurry outlet  41  to which a hydrotransport conduit (not shown) is detachably coupled by suitable means, for example a bolted flange. 
         [0122]    An ore size regulating apparatus such as a screen or comminuting apparatus  50  is suspended above the slurry box  30 . For example, in the preferred embodiment the comminuting apparatus may be a screening/sizing roller screen such as that described in Canadian Patent Application No. 2,476,194 entitled “SIZING ROLLER SCREEN ORE PROCESSING” published Jan. 30, 2006, which is incorporated herein by reference, which both screens and crushes ore. In the preferred embodiment the comminuting apparatus  50  is supported on the frame  20  of the slurry apparatus  10 , with the output face of the comminuting apparatus  50  in communication with the open top of the slurry box  30  such that comminuted ore fed to the comminuting apparatus  50  is directed into the slurry box  30  under the force of gravity. Alternatively, as screen may be provided to screen the incoming ore flow as an initial step before crushing. 
         [0123]    Because the slurry apparatus  10  according to the invention is movable, it is advantageous to maintain a low centre of gravity in the slurry apparatus  10  and therefore if the comminuting apparatus  50  is suspended above the slurry box  30  it is advantageous to provide the comminuting apparatus  50  as close as possible (vertically) to the open top of the slurry box  30 . The comminuting apparatus  50  may be oriented close to the horizontal, or alternatively may have either a positive or negative angle to the horizontal. In a preferred embodiment the comminuting apparatus  50  is oriented at an angle to the horizontal such that comminuted ore is fed at the higher end of the comminuting apparatus  50 . The comminuting apparatus  50  may be supported on its own separate frame, may be solely supported by a side  24  of the slurry apparatus frame  20 , or may be supported on the slurry box  30 . Alternatively, the comminuting apparatus  50  may be in communication with the slurry box  30  via one or more interposed conveyor mechanisms, such as a transfer conveyor (not shown). 
         [0124]    The comminuting apparatus  50  may alternatively be housed in a separate structure and maintained in communication with the slurry box  30  by a conveying apparatus such as a transfer conveyor (not shown). Similarly, while the illustrated embodiment shows the slurry pump  39  and electrical transformers  9  housed in the structure of the slurry facility  10 , it is possible to house these components in one or more separate structures that are detachably connected to the relevant systems in the slurry facility  10  when the slurry facility  10  is in operating mode. It is advantageous to provide transformers  9  within or immediately adjacent to the slurry facility  10 , which will gradually be moved away from any permanent transformer substation as mining progresses. 
         [0125]    A water supply  60 , for example a hood with a spray header (shown in  FIG. 14 ), is positioned to apply hot process water to the ore as it is fed into the comminuting apparatus  50 , assisting in the comminuting process and so that ore is already wetted when it enters slurry box  30 . As is well known in the art, the hot process water is mixed with the ore in a proportion which provides the desired slurry consistency for conditioning during transport to an extraction facility. The water supply  60  may be provided in any convenient location for dispensing the process water over the ore, preferably before comminution or optionally after comminution. 
         [0126]    The slurry box  30  is mounted to the floor  22  of the slurry apparatus frame  20  in the desired position. As illustrated in  FIG. 14 , the frame  20  is supported on a first set of spaced apart support points  21 , for example adjacent to the corners where the sides  24  meet the base  22 , which may be mounted on crane mats  23  as in the embodiment illustrated in  FIGS. 13 and 14 , to support the frame  20  in stationary mode, or alternatively may be mounted on pontoons  27  or other suitable support. The slurry box  30  may be disposed anywhere within the frame  20 , as long as the centre of gravity CG 1  of the slurry apparatus  10  when the slurry box  30  is filled is within the area bounded by the first set of spaced apart support points  21  (as shown in  FIG. 14 ). 
         [0127]    The frame  20  further contains other apparatus incidental to the operation of the slurry facility, which may for example include a gland water supply for the slurry pump  39 , cooling units for conditioning the air within the facility to make it suitable for workers, electrical transformers for powering the equipment used in the slurry facility  10 , safety equipment, overhead cranes for maintenance and so on. The distribution of equipment about the frame  20  of the slurry apparatus  10  determines a first center of gravity CG 1  for the slurry apparatus  10  in a stationary mode, in which the slurry box  30  is filled and operational. Preferably the amount and size of equipment are minimized to keep the weight of the facility  10  as low as possible; for example, the facility  10  may house a single hydrotransport pump  39  (or the hydrotransport pump  39  may be supported on a separate structure as noted above). The heaviest equipment should be as low as possible within the frame  20 , to keep the centre of gravity CG 1  and CG 2  low. In the stationary mode, when the frame  20  is supported on the first set of spaced apart support points  21  and the slurry box  30  is filled with slurry and operational, a considerable additional amount of weight is concentrated in the region of the slurry box  30 , which determines the position of the first center of gravity CG 1 . The frame  20  thus supports all the on-board equipment, plus the weight of the slurry, on the first set of spaced apart support points  21 . 
         [0128]    In a moving mode, with the slurry box  30  empty, the centre of gravity is disposed at CG 2 . The base  22  of the frame  20  is provided with a lifting region  70 , shown in  FIG. 15 , which is formed by a series of beams affixed to the main girders  28  of the base  22 . The entire slurry apparatus  10  can thus be lifted by a single moving device such as a mobile crawler  80 , for example that produced by Lampson International LLC (hereinafter referred to as a “Lampson Crawler”), lifting solely at the lifting region  70 , without substantial deformation of the frame  20 . The lifting region  70  defines a second set of spaced apart support points  72 , which is directly beneath (and preferably centered under) the second center of gravity CG 2 . The Lampson Crawler, which is essentially a hydraulic lifting platform having a propulsion system and mounted on tracks as illustrated in  FIG. 9B , can be positioned under the lifting region  70  using locator tabs  74 , shown in  FIG. 15 , and raised to lift the frame  20  while maintaining the stability of the facility  10 . 
         [0129]    In the operating mode, ore is fed to the comminuting apparatus  50  in any desired fashion, for example via a transfer conveyor  6  as shown in  FIGS. 13 and 4 . Preferably the transfer conveyor  6  is freestanding and not connected to the slurry apparatus  10 , but suspended in communication with the slurry apparatus  10 . The ore is processed by the comminuting apparatus  50 , preferably to reduce the particle size of the entire inflow of ore to a maximum of 2″ to 2½″ (although larger ore sizes can also be processed). The comminuting apparatus  50  may include an oversize comminuting component  52  (shown in  FIG. 14 ) to comminute oversized ore and eliminate rejected ore. 
         [0130]    The comminuted ore is mixed with water from the water supply  60  and fed into the slurry box  30 . A slurry of the consistency desired for hydrotransport is thus created within the slurry box  30 . The slurry progresses through the slurry box  30  over the selected retention interval and egresses through the slurry outlet to a hydrotransport pump  39 , which in turn feeds the slurry into a hydrotransport outlet  41  to which a line (not shown) is detachably connected for transport to an extraction facility (not shown). The hydrotransport line is detachable from the hydro transport outlet  41  to allow for periodic movement of the slurry apparatus  10  to a new site as the mine face moves away from the slurry apparatus  10 . 
         [0131]    The electrical supplies including all power lines (and optionally telecommunications cables) are preferably contained in a power cable that detachably connects to a local connection (not shown) on the slurry facility  10 , which may for example be adjacent to the transformers  9 , to facilitate easy connection and disconnection of all electrical systems to a standard power source remote to the movable facility  10 . Preferably the electrical power system is grounded via cable to a local transformer station or platform, rather than directly into the ground, either via the power cable or via a separate grounding cable, to facilitate detachment and reattachment of the ground connection during the relocation procedure. Similarly, water supplies and connections to fluid outlets (for example emergency pond outlet  45 ) are not welded but are instead detachably coupled via bolted flanges, quick-connect couplings or other suitable detachable connections as desired to facilitate detachment and reattachment during the relocation procedure. 
         [0132]    When it is desired to move the slurry apparatus  10  to a new location, the transfer conveyor  6  is deactivated to discontinue the ore flow, and the slurry box  30  is empty and flushed. Preferably the slurry apparatus  10  includes a cold water supply  43  for use in flushing the slurry apparatus (and in case of emergency; an emergency outlet  45  is also preferably provided for directing contaminated water to a nearby emergency pond if needed). When the slurry box  30  has been completely emptied and flushed, the hydrotransport line (not shown) is disconnected from hydrotransport pump  39 . 
         [0133]    All electrical and water supplies are disconnected from the apparatus  10 . Once all water supplies and electrical supplies have been disconnected, the slurry apparatus  10  is ready to be moved to a new location. 
         [0134]    A path to the new location is prepared, for example by compacting and laying down a suitable bed of gravel, if necessary. The new location is surveyed to ensure it is level (using gravel if necessary to level the site), and in the embodiment illustrated in  FIGS. 13 and 14  crane mats are laid optionally covered by metal sheeting (not shown) to avoid point-loading the crane mats  23 . In this embodiment hydraulic jacks  29  are provided generally under the first set of spaced apart support points, supported on the crane mats  23 . The jacks  29  are actuated, either in unison or individually in increments, to raise the frame  20  to a height that will allow a moving device  80  such as a Lampson Crawler, with its hydraulic platform  82  in retracted mode, to be driven beneath the base  22  of the frame  20  and positioned under the lifting region  70  using locator tabs  74  (shown in  FIG. 15 ) as a guide to position the hydraulic platform  82 . The hydraulic platform  82  is raised, lifting the entire frame  20 . When the frame  20  has been raised to support the frame the hydraulic jacks  29  are retracted (as shown in  FIG. 16 ), the propulsion system in the Lampson Crawler  80  is engaged and the slurry apparatus  10  is moved toward the new location. Preferably the slurry apparatus  10  comprises on-board levels (not shown) at locations visible from the exterior of the apparatus  10 , and/or a water level comprising a flexible tube filled with water and extending across the entire frame  20  (not shown), which are carefully monitored by operators to ensure that the facility  10  remains level within the tolerances permitted by the second set of spaced apart support points  72  (as described below). 
         [0135]    As illustrated in  FIG. 16  the slurry apparatus  10  may be tilted, preferably up to or potentially more than 8° from the vertical, while maintaining the center of gravity in moving mode CG 2  over the lifting region  70 . This allows the slurry apparatus  10  to be moved up or down a grade, and to tolerate variations of the ground surface. The hydraulic lifting platform  82  on the Lampson Crawler also has the ability to lift differentially, and thus compensate to some extent for the angle of a grade as shown in  FIG. 16 . However, the slurry apparatus  10  itself may be tilted up to the point where the center of gravity CG 2  reaches the periphery of the lifting region  70 , beyond which the apparatus  10  will become unstable. 
         [0136]    When the new site is reached the hydraulic jacks  29  are extended to support the frame on the crane mats  23  which have been placed on the ground beneath the first set of support points  21 , the hydraulic lifting platform  82  is lowered and the Lampson Crawler is driven away from the site. The slurry facility  10  is fully supported by the first set of spaced apart support points  21 , and can be returned to the operating mode by extending (from the previous site) and reconnecting the hydrotransport line and all electrical and water supplies. An ore feeder such as a transfer conveyor is positioned in communication with the comminuting apparatus  50 , and operation of the slurry facility  10  is resumed. When the slurry box  30  is once again filled with slurry, the center of gravity will shift from CG 2  back to CG 1 , shown in  FIG. 14 . 
         [0137]    In a further embodiment of the apparatus, the frame  20  is provided with pontoons  27  onto which the frame  20  is set instead of crane mats  23 . This reduces the steps required to both lift the slurry apparatus  10  and to prepare the new relocation site. This also has the advantage of adding weight to the bottom of the frame  20 , lowering the centres of gravity CG 1  and CG 2 . The operation of this embodiment is otherwise as previously described. 
         [0138]    A suitable system, apparatus and process for extraction is described and claimed in applicant&#39;s co-pending application entitled SYSTEM, APPARATUS AND PROCESS FOR EXTRACTION OF BITUMEN FROM OIL SANDS, filed Nov. 9, 2006 and claiming priority from CA2,526,336. 
         [0139]    A preferred embodiment of the invention having been thus described by way of example only, it will be appreciated that variations and permutations may be made without departing from the invention, as set out in the appended claims. All such variations and permutations are intended to be included within the scope of the invention.