Field of the invention:

The present invention relates to a deposition method for applications typically used in of the oil and gas industry. More particularly, the present invention relates to a method and to a corresponding device for improving the deposition of flocculated oil sand fine tailings (hereinafter referred to also as flocculated "mature fine tailings" (MFT)) into a deposition containment area, such a deposition cell, for example.

Background of the invention:

Oil sand fine tailings have become a technical, operational, environmental, economic and public policy issue.

Oil sand tailings are generated from hydrocarbon extraction process operations that separate the valuable hydrocarbons from oil sand ore. All commercial hydrocarbon extraction processes use variations of the Clark Hot Water Process in which water is added to the oil sands to enable the separation of the valuable hydrocarbon fraction from the oil sand minerals. The process water also acts as a carrier fluid for the mineral fraction. Once the hydrocarbon fraction is recovered, the residual water, unrecovered hydrocarbons and minerals are generally referred to as "tailings".

The oil sand industry has adopted a convention with respect to mineral particle sizing. Mineral fractions with a particle diameter greater than 44 microns are referred to as "sand". Mineral fractions with a particle diameter less than 44 microns are referred to as "fines". Mineral fractions with a particle diameter less than 2 microns are generally referred to as "clay", but in some instances "clay" may refer to the actual particle mineralogy. The relationship between sand and fines in tailings reflects the variation in the oil sand ore make-up, the chemistry of the process water and the extraction process.

Conventionally, tailings are transported to a deposition site generally referred to as a "tailings pond" located close to the oil sands mining and extraction facilities to facilitate pipeline transportation, discharging and management of the tailings. Due to the scale of operations, oil sand tailings ponds cover vast tracts of land and must be constructed and managed in accordance with regulations. The management of pond location, filling, level control and reclamation is a complex undertaking given the geographical, technical, regulatory and economic constraints of oil sands operations. Each tailings pond is contained within a dyke structure generally constructed by placing the sand fraction of the tailings within cells or on beaches. The process water, unrecovered hydrocarbons, together with sand and fine minerals not trapped in the dyke structure flow into the tailings pond. Tailings streams initially discharged into the ponds may have fairly low densities and solids contents, for instance around 0.5-10 wt%.

In the tailings pond, the process water, unrecovered hydrocarbons and minerals settle naturally to form different strata. The upper stratum is primarily water that may be recycled as process water to the extraction process. The lower stratum contains settled residual hydrocarbon and minerals which are predominately fines. This lower stratum is often referred to as "mature fine tailings" (MFT). Mature fine tailings have very slow consolidation rates and represent a major challenge to tailings management in the oil sands industry.

The composition of mature fine tailings is highly variable. Near the top of the stratum the mineral content is about 10 wt% and through time consolidates up to 50 wt% at the bottom of the stratum. Overall, mature fine tailings have an average mineral content of about 30 wt%. While fines are the dominant particle size fraction in the mineral content, the sand content may be 15 wt% of the solids and the clay content may be up to 75 wt% of the solids, reflecting the oil sand ore and extraction process. Additional variation may result from the residual hydrocarbon which may be dispersed in the mineral or may segregate into mat layers of hydrocarbon. The mature fine tailings in a pond not only has a wide variation of compositions distributed from top to bottom of the pond but there may also be pockets of different compositions at random locations throughout the pond.

Mature fine tailings behave as a fluid-like colloidal material. The fact that mature fine tailings behave as a fluid significantly limits options to reclaim tailings ponds. In addition, mature fine tailings do not behave as a Newtonian fluid, which makes continuous commercial scale treatments for dewatering the tailings all the more challenging. Without dewatering or solidifying the mature fine tailings, tailings ponds have increasing economic and environmental implications over time.

There are some methods that have been proposed for disposing of or reclaiming oil sand tailings by attempting to solidify or dewater mature fine tailings. If mature fine tailings can be sufficiently dewatered so as to convert the waste product into a reclaimed firm terrain, then many of the problems associated with this material can be curtailed or completely avoided. As a general guideline target, achieving a solids content of 75 wt% for mature fine tailings is considered sufficiently "dried" for reclamation.

One known method for dewatering MFT involves a freeze-thaw approach. Several field trials were conducted at oil sands sites by depositing MFT into small, shallow pits that were allowed to freeze over the winter and undergo thawing and evaporative dewatering the following summer. Scale up of such a method would require enormous surface areas and would be highly dependent on weather and season. Furthermore, other restrictions of this setup were the collection of release water and precipitation on the surface of the MFT which discounted the efficacy of the evaporative drying mechanism.

Some other known methods have attempted to treat MFT with the addition of a chemical to create a thickened paste that will solidify or eventually dewater. One such method, referred to as "consolidated tailings" (CT), involves combining mature fine tailings with sand and gypsum. A typical consolidated tailings mixture is about 60 wt% mineral (balance is process water) with a sand to fines ratio of about 4 to 1 , and about 600 to 1000 ppm of gypsum. This combination can result in a non-segregating mixture when deposited into the tailings ponds for consolidation. However, the CT method has a number of drawbacks. It relies on continuous extraction operations for a supply of sand, gypsum and process water. The blend must be tightly controlled. Also, when consolidated tailings mixtures are less than 60 wt% mineral, the material segregates with a portion of the fines returned to the pond for reprocessing when settled as mature fine tailings. Furthermore, the geotechnical strength of the deposited consolidated tailings requires containment dykes and, therefore, the sand required in CT competes with sand used for dyke construction until extraction operations cease. Without sand, the CT method cannot treat mature fine tailings.

Another method conducted at lab-scale sought to dilute MFT preferably to 10 wt% solids before adding Percol LT27A or 156. Though the more diluted MFT showed faster settling rates and resulted in a thickened paste, this dilution- dependent small batch method could not achieve the required dewatering results for reclamation of mature fine tailings.

Some other methods have attempted to use polymers or other chemicals to help dewater MFT. However, these methods have encountered various problems and have been unable to achieve reliable results. When generally considering methods comprising chemical addition followed by tailings deposition for dewatering, there are a number of important factors that should not be overlooked.

Of course, one factor is the nature, properties and effects of the added chemicals. The chemicals that have shown promise up to now have been dependent on oil sand extraction by-products, effective only at lab-scale or within narrow process operating windows, or unable to properly and reliably mix, react or be transported with tailings. Some added chemicals have enabled thickening of the tailings with no change in solids content by entrapping water within the material, which limits the water recovery options from the deposited material. Some chemical additives such as gypsum and hydrated lime have generated water runoff that can adversely impact the process water reused in the extraction processes or dried tailings with a high salt content that is unsuitable for reclamation.

Another factor is the chemical addition technique. Known techniques of adding sand or chemicals often involve blending materials in a tank or thickener apparatus. Such known techniques have several disadvantages including requiring a controlled, homogeneous mixing of the additive in a stream with varying composition and flows which results in inefficiency and restricts operational flexibility. Some chemical additives also have a certain degree of fragility, changeability or reactivity that requires special care in their application. Another factor is that many chemical additives can be very viscous and may exhibit non-Newtonian fluid behaviour. Several known techniques rely on dilution so that the combined fluid can be approximated as a Newtonian fluid with respect to mixing and hydraulic processes. Mature fine tailings, however, particularly at high mineral or clay concentrations, demonstrates non-Newtonian fluid behaviour. Consequently, even though a chemical additive may show promise as a dewatering agent in the lab or small scale batch trials, it is difficult to repeat performance in an up-scaled or commercial facility. This problem was demonstrated when attempting to inject a viscous polymer additive into a pipe carrying MFT. The main MFT pipeline was intersected by a smaller side branch pipe for injecting the polymer additive. For Newtonian fluids, one would expect this arrangement to allow high turbulence to aid mixing. However, for the two non-Newtonian fluids, the field performance with this mixing arrangement was inconsistent and inadequate. There are various reasons why such mixing arrangements encounter problems. When the additive is injected in such a way, it may have a tendency to congregate at the top or bottom of the MFT stream depending on its density relative to MFT and the injection direction relative to the flow direction. For non-Newtonian fluids, such as Bingham fluids, the fluid essentially flows as a plug down the pipe with low internal turbulence in the region of the plug. Also, when the chemical additive reacts quickly with the MFT, a thin reacted region may form on the outside of the additive plug thus separating unreacted chemical additive and unreacted MFT.

Inadequate mixing can greatly decrease the efficiency of the chemical additive and even short-circuit the entire dewatering process. Inadequate mixing also results in inefficient use of the chemical additives, some of which remain unmixed and unreacted and cannot be recovered. Known techniques have several disadvantages including the inability to achieve a controlled, reliable or adequate mixing of the chemical additive as well as poor efficiency and flexibility of the process. Still another factor is the technique of handling the oil sand tailings after chemical addition. If oil sand tailings are not handled properly, dewatering may be decreased or altogether prevented. In some past trials, handling was not managed or controlled and resulted in unreliable dewatering performance. Some techniques such as in CIBA's Canadian patent application No. 2,512,324 (SCHAFFER et al.) have attempted to simply inject the chemical into the pipeline without a methodology to reliably adapt to changing oil sand tailings compositions, flow rates, hydraulic properties or the nature of particular chemical additive. Relying solely on this ignores the complex nature of mixing and treating oil sand tailings and significantly hampers the flexibility and reliability of the system. When the chemical addition and subsequent handling have been approached in such an uncontrolled, trial-and-error fashion, the dewatering performance has been unachievable.

Yet another factor is the technique of handling or treating the MFT prior to chemical addition. MFT is drawn up by pumps or dredging equipment from tailings ponds and preferably sent via pipeline to the dewatering treatment area. The tailings ponds, however, may contain a variety of materials that could disrupt the MFT dewatering process. For instance, in the raw MFT there may be mats of bitumen, particularly in the cold winter months. There may also be other extraneous debris such as pieces of wood, glass, plastic, metal or natural organic material that can be entrained with the MFT as it is taken from the pond. Such unwanted materials can interfere with the MFT process equipment and chemistry.

Given the significant inventory and ongoing production of MFT at oil sands operations, there is a need for techniques and advances that can enable MFT drying for conversion into reclaimable landscapes.

Known to the applicant are the following publications and patent documents, namely: OWEN, A . et al. "Using turbulent pipe flow to study the factors affecting polymer-bridging flocculation of mineral systems", International Journal of Mineral Processing, Vol. 87, Issues 3-4, July 2 ^nd , 2008; VRALE et al., "Rapid Mixing in Water, " Jour. AWWA, Jan., 1971 ; WO 2002/079099 A1 (BRANNING, L); WO 2009/009887 A1 (BOZAK, R. et al.); and US 5,839,828 (GLANVILLE, R.).

However, none of these prior art documents seem to teach, illustrate or even suggest a solution which is intended to improve the deposition of flocculated mature fine tailings into a deposition containment area, in a simple, efficient and cost- effective manner. Indeed, it is known in the art that in the case of tailings reduction operations, extra mixing of the MFT and flocculent agent, such as polymer for example, are often required at a point in the process where the fluid medium is highly sensitive to shear forces, namely just prior to cell deposition. Typical in-line mixing devices introduce high amounts of shear forces which tend to break up the flocculated MFT in their attempt to provide mixing, such break up being very disadvantageous and undesirable for obvious reasons. Therefore, it would be very useful to provide a solution that enables improved mixing of un-reacted polymer while minimizing additional shear forces on the existing mixed material. Hence, in light of the aforementioned, there is a need for a new method or device which would be able to overcome or at least minimize some of the above- discussed prior art concerns.

Summary of the invention:

An object of the present invention is to provide a device, which by virtue of its design and components, satisfies some of the above-mentioned needs and is thus an improvement over other related devices and/or methods known in the prior art.

In accordance with the present invention, the above object is achieved, as will be easily understood, with a device such as the one briefly described herein, and such as the one exemplified in the accompanying drawings. More particularly, the present invention relates to a deposition device for an additional mixing of mature fine tailings with residual flocculating agent prior to depositing into a deposition cell, the deposition device comprising:

- an inlet for receiving a fluid flow of flocculated mature fine tailings and residual flocculating agent from an in-line feed; - an accumulation chamber for accumulating the fluid flow from the inlet, the accumulation chamber being configured for reducing the flow velocity of the fluid flow and for raising said fluid flow up to a predetermined height;

- an overflow interface provided at the predetermined height for allowing the fluid flow to overflow from the accumulation chamber; and

- a descent assembly for receiving the fluid flow overflowing from the accumulation chamber via the overflow interface, and for allowing said fluid flow to descend to at least one lower height, the descent assembly being configured so that residual flocculating agent from the fluid flow is additionally mixed with mature fine tailings from said fluid flow when the fluid flow is traveling down the descent assembly from an upper region to a lower region, the descent assembly being further configured for preventing overshearing of the flocculated mature fine tailings prior to depositing into the deposition cell. According to another aspect of the present invention, there is also provided a kit with components for assembling the above-mentioned injection device.

According to yet another aspect of the present invention, there is also provided a conversion kit including the above-mentioned device and/or components.

According to yet another aspect of the present invention, there is also provided a set of components for interchanging with components of above- mentioned device and/or kit.

According to yet another aspect of the present invention, there is also provided a method for assembling components of the above-mentioned kit and/or set. According to yet another aspect of the present invention, there is also provided a method of using the above-mentioned device, kit, set and/or components thereof.

According to yet another aspect of the present invention, there is also provided a corresponding pipeline carrying flocculated mature fine tailings, the pipeline having been assembled with the above-mentioned device, conversion kit, set and/or method(s).

According to yet another aspect of the present invention, there is also provided a method of manufacturing the above-mentioned device, corresponding kit and/or conversion set.

According to yet another aspect of the present invention, there is also provided a method of treating a fluid flow of flocculated mature fine tailings prior to depositing.

More particularly, the present invention also relates to a method for additionally mixing mature fine tailings with residual flocculating agent prior to depositing into a deposition cell, the method comprising the steps of:

a) receiving a fluid flow of flocculated mature fine tailings and residual flocculating agent from an in-line feed;

b) reducing the flow velocity of the fluid flow and accumulating said fluid flow inside a chamber up to a predetermined height; and

c) allowing the fluid flow to flow down a descent assembly so as to descend from the predetermined height to at least one lower height, the descent assembly being configured so that residual flocculating agent from the fluid flow is additionally mixed with mature fine tailings from said fluid flow when the fluid flow travels down the descent assembly from an upper region to a lower region, the descent assembly being further configured for preventing overshearing of the flocculated mature fine tailings.

The objects, advantages and other features of the present invention will become more apparent upon reading of the following non-restrictive description of preferred embodiments thereof, given for the purpose of exemplification only, with reference to the accompanying drawings.

Brief description of the drawings:

Figure 1 is a front perspective view of a deposition device according to a first preferred embodiment of the present invention.

Figure 2 is rear perspective view of what is shown in Figure 1.

Figure 3 is a front perspective view of a housing according to a preferred embodiment of the present invention.

Figure 4 is an elevational view of a side wall of a housing provided with a pair of lifting components according to a preferred embodiment of the present invention.

Figure 5 is a top view of what is shown in Figure 3.

Figure 6 is a rear view of what is shown in Figure 3.

Figure 7 is a perspective view of a base according to a preferred embodiment of the present invention. Figure 8 is a side elevational view of what is shown in Figure 7.

Figure 9 is top view of what is shown in Figure 7. Figure 0 is a perspective view of a lifting component according to a preferred embodiment of the present invention.

Figure 11 is a side view of what is shown in Figure 10.

Figure 12 is a front view of what is shown in Figure 10. Figure 13 is a top view of what is shown in Figure 10.

Figure 14 is a front view of a lifting lug of the lifting component shown in Figure 10.

Figure 15 is a top view of what is shown in Figure 14.

Figure 16 is a perspective view of a partitioning wall having opposite side edges removably mounted onto corresponding opposite slots each being defined by a pair of corresponding guides according to a preferred embodiment of the present invention.

Figure 17 is a front view of what is shown in Figure 16.

Figure 18 is a top view of what is shown in Figure 16. Figure 19 is a schematic representation of a base of a housing of a deposition device provided with at least one reinforcement component according to a preferred embodiment of the present invention.

Figure 20 is a side view of the reinforcement component shown in Figure 19.

Figure 21 is a front view of what is shown in Figure 20. Figure 22 is a perspective view of a flange connection intended to be used with an inlet of a deposition device according to a preferred embodiment of the present invention.

Figure 23 is a side view of what is shown in Figure 22.

Figure 24 is a front view of what is shown in Figure 23.

Figure 25 is a perspective view of a deposition device according to another preferred embodiment of the present invention.

Figure 26 is a top view of what is shown in Figure 25.

Figure 27 is a side view of what is shown in Figure 25.

Figure 28 is a front view of what is shown in Figure 25.

Figure 29 is a partial cross-sectional view taken along a longitudinal axis of the deposition device shown in Figure 25.

Figure 30 is a top perspective view of a deposition device according to yet another preferred embodiment of the present invention.

Figure 31 is a side elevational view of what is shown in Figure 30.

Figure 32 is a top plan view of what is shown in Figure 30.

Figure 33 is a front view of what is shown in Figure 30.

Figure 34 is a top perspective view of the vertical pipe, corresponding feed pipe and supports, shown in Figure 30. Figure 35 is a side elevational view of what is shown in Figure 34.

Figure 36 is a front view of what is shown in Figure 34.

Figure 37 is a top plan view of what is shown in Figure 34.

Figure 38 is an enlarged front view of a portion of what is shown in Figure 34.

Figure 39 is another top perspective view of what is shown in Figure 34, the cut-out portion of the vertical pipe being now shown provided with a corresponding spill box according to a preferred embodiment of the present invention.

Figure 40 is an enlarged perspective view of the spill box shown in Figure 39.

Figure 41 is a cross-sectional view taken along a central line of what is shown in Figure 40.

Figure 42 is a front view of what is shown in Figure 40.

Figure 43 is a top view of what is shown in Figure 40.

Figure 44 is a perspective view of the ramp assembly shown in Figure 30.

Figure 45 is a side elevational view of what is shown in Figure 44.

Figure 46 is a top plan view of what is shown in Figure 44.

Figure 47 is a front view of what is shown in Figure 44.

Figure 48 is a top plan view of a ramp assembly according to a preferred embodiment of the present invention. Figure 49 is a side view of a deposition device according to yet another preferred embodiment of the present invention.

Figure 50 is a top plan view of what is shown in Figure 49.

Figure 51 is an enlarged front view of a portion of what is shown in Figure 49. Detailed description of preferred embodiments of the invention:

In the following description, the same numerical references refer to similar elements. The embodiments, geometrical configurations, materials mentioned and/or dimensions shown in the figures are preferred, given for exemplification purposes only. Moreover, although the present invention was primarily designed for improving deposition of flocculated mature fine tailings (MFT) into a deposition containment area, for example, it may be used with other types of substance(s) and/or liquid(s), for other purposes, and in other fields, as apparent to a person skilled in the art. For this reason, expressions such as "depositing", "flocculated", "MFT", etc. used herein should not be taken as to limit the scope of the present invention and includes all other kinds of pipelines, cylinders, items and/or applications with which the present invention could be used and may be useful.

Moreover, in the context of the present invention, the expressions "device", "kit", "unit", "cascade", "box", "slide", "ramp", "apparatus", "mechanism", "assembly", "system", "set" and any other equivalent expression and/or compound word thereof known in the art will be used interchangeably. Furthermore, the same applies for any other mutually equivalent and/or complementary expressions, such as "MFT", "fluid flow", "material", "medium" and "fluid", as well as "polymer" and "flocculating agent" for example, or even "deposit", "discharge", "overflow" and "release", as well as "mixed", "reacted" and "used", as also apparent to a person skilled in the art.

In addition, although the preferred embodiment of the present invention as illustrated in the accompanying drawings comprises various components and although the preferred embodiment of the deposition device as shown consists of certain geometrical configurations as explained and illustrated herein, not all of these components and geometries are essential to the invention and thus should not be taken in their restrictive sense, i.e. should not be taken as to limit the scope of the present invention. It is to be understood that other suitable components and cooperations thereinbetween, as well as other suitable geometrical configurations may be used for the deposition device and corresponding parts according to the present invention, as well as corresponding conversion kit or set, and/or resulting pipeline or fitting, as briefly explained herein, or as can be easily inferred herefrom, by a person skilled in the art, without departing from the scope of the present invention.

List of numerical references for some of the corresponding preferred components illustrated in the accompanying drawings:

1. deposition device

3. deposition cell

5. inlet

7. fluid flow

9. accumulation chamber

11. overflow interface

13a. predetermined height

13b. lower height

15. descent assembly

15i. cascading assembly ii. ramp assembly

a. upper region

b. lower region

. step

b. integrated step (of housing 25)

. riser

a. uppermost riser

b. integrated riser (of housing 25)

. partitioning plate

a. drainage hole (of partitioning plate 23)

. housing

a. left side wall (of housing 25)

b. right side wall (of housing 25)

c. end wall (of housing 25)

d. bottom wall

. slot

a. first guide

b. second guide

. reinforcement component (of partitioning plate 23) . top edge (of uppermost riser 2 a)

. base

. flange connection

. reinforcement component (of housing)

. lifting component

. skid base

. top portion (of ramp assembly 15ii)

. bottom portion (of ramp assembly 15ii)

. ramp (of ramp assembly 15ii)

. ridge (of ramp assembly 15ii) 51. longitudinal axis (of ramp assembly 15ii)

53. containment wall (of ramp assembly 15ii)

55. vertical pipe

57. upper cut-out portion (of vertical pipe 55)

59. spill box

61. pin (of spill box 59)

63. hole (of top portion of ramp 47)

65. abutment flange(of spill box 59)

67. feed pipe (of vertical pipe 55)

69. inside portion (of vertical pipe 55)

71. support (of vertical pipe 55)

73. apertures (of vertical pipe 55)

73a. first set of apertures

73b. second set of apertures

Θ. angle

Broadly described, as exemplified in the accompanying drawings and as can be easily understood herefrom by a person skilled in the art, the present invention relates to a deposition method for improving the depositing of flocculated oil fine tailings, hereinafter referred to also as flocculated "mature fine tailings" (MFT), into a deposition containment area having a deposition surface, such as a deposition cell, for example. Indeed, it is well known in the art that in the case of tailings reduction operations, extra mixing of the MFT and flocculent agent, such as a polymer for example, are often required at a point in the process where the fluid medium is highly sensitive to shear forces, namely just prior to cell deposition. Typical in-line mixing devices introduce high amounts of shear forces which tend to break up the flocculated MFT in their attempt to provide mixing, such break up being very disadvantageous and undesirable for obvious reasons. Therefore, the present invention aims to provide an improved mixing of un-reacted polymer while minimizing additional shear forces on the existing flocculated material.

According a preferred aspect of the invention, the method is intended for additionally mixing mature fine tailings with residual flocculating agent which may still be left in the fluid flow (7) of the pipeline carrying the flocculated mature fine tailings prior to depositing, in order to not only advantageously use such residual flocculating agent which would normally go unused and end up in the deposition cell, but also for providing additional flocculation of the mature fine tailings via a mixing with the residual flocculating agent for improved dewatering purposes, MFT drying, etc. The method according to the present invention preferably comprises the steps of: a) receiving a fluid flow (7) of flocculated mature fine tailings and residual flocculating agent from an in-line feed, such as a pipeline for example; b) reducing the fluid velocity of the fluid flow (7) and accumulating said fluid flow (7) inside a chamber (9) (or a vertical pipe (55), etc.) up to a certain predetermined height (13a); and c) allowing the fluid flow (7) to flow down a descent assembly (15) so as to descend from the starting predetermined height (13a) to at least one lower height (13b), and preferably a plurality or a "cascade" of such lower heights (13b), the descent assembly (15) being configured so that residual flocculated agent which may be present in the fluid flow (7) is additionally mixed with mature fine tailings from said fluid flow (7) when the fluid flow (7) travels down the descent assembly (15) from an upper region (17a) to a lower region (17b), the descent assembly (15) being further configured for preventing overshearing of the flocculating mature fine tailings, thereby enabling to have a gentle mixing of the mature fine tailings with the flocculating agent, such as a polymer for example, which would otherwise be wasted with conventional methods of operation. Indeed, as will be better appreciated in greater detail hereinbelow, the present invention is intended namely to prevent overshearing of flocculated MFT/polymer mixture at the cell deposition point, and also reduce unmixed polymer from entering the deposition cell. It is worth mentioning at this point that although a polymer has been given as a way of an example for a possible flocculating agent for the mature fine tailings, a person skilled in the art would understand that various other types of flocculating agents, solutions, elements, compounds and/or the like, may be used according to the present invention in order to provide an additional mixing (reaction, flocculation, etc.) of the mature fine tailings with a corresponding suitable flocculating agent, depending on the particular applications for which the present method is intended for, the factors in place and the desired end results.

Preferably, step a) of the present invention comprises a step of exposing the fluid flow (7) to atmospheric pressure, and steps b) and c) can be done either separately, or simultaneously, as apparent to a person skilled in the art. Preferably also, the present method further comprises the step of: d) subsequently depositing the fluid flow (7) into a deposition cell, for example. It is worth mentioning that although the present deposition device (1 ) could be designed to be operated in a closed system, it is preferable to have the deposition device (1 ) open to atmosphere because this provides different advantages. Namely, it allows for an easier cleanout. Furthermore, it also provides for an aeration of the material which is believed to aid in dewatering. Moreover, having a deposition device (1 ) which is open to atmosphere allows for the different components thereof to be more easily accessible, inspected, maintained and/or replaced, if need may be.

According to another aspect of the present invention, there is also provided a deposition method for improving the depositing of flocculated oil fine tailings into a deposition containment area having a deposition surface, the deposition method comprising: a) providing an in-line continuous flow of material comprising flocculated oil sand fine tailings; b) providing a chamber comprising a lower region, and an upper region located above and interfacing with the lower region; c) introducing the material into the lower region of the chamber to allow reduction in velocity and mixing of the material therein; and d) allowing the material to fill and spill out of the upper region of the chamber so as to avoid overshear of the flocculated fine tailings when the material is spilled onto a deposition surface.

The present invention also relates to corresponding a deposition device (1 ) which may come in various suitable shapes and forms for carrying out the different methods briefly described herein. For example, the present description describes three main embodiments of a deposition device (1 ) and corresponding descent assembly (15) according to the present invention, the first one being exemplified in Figures 1-29 and hereinafter referred to also as a "cascade box", the second one being exemplified in Figures 30-48, and hereinafter referred to also as a "deposition slide", and the third one being exemplified in Figures 49-51 , and referred to hereinafter also as "stand pipe". The following description will provide more insight as to the various aspects, possible variants and resulting advantages of each one of these preferred embodiments of the present invention.

Generally speaking, and according to a first given preferred aspect of the present invention, the deposition device (1 ) is intended for additional mixing of mature fine tailings with residual flocculating agent prior to depositing into a deposition cell. As can be easily understood by a person skilled in the art in view of the accompanying drawings, the deposition device (1 ) preferably comprises an inlet (5), an accumulation chamber (9), an overflow interface (11 ) and a descent assembly (15). The inlet (5) is intended for receiving a fluid flow (7) of flocculated mature fine tailings and residual flocculated agent from an in-line feed, such as a pipeline carrying the fluid flow (7) to be treated and processed with the present deposition device (1 ) prior to depositing into a deposition cell, for example. The accumulation chamber (9) is intended for accumulating the fluid flow (7) from the inlet (5), and is preferably configured for reducing the flow velocity of the fluid flow (7) and for raising said fluid flow (7) up to a certain predetermined height (13a). Preferably also, the overflow interface (11 ) is provided at the predetermined height (13a) for allowing the fluid flow (7) to overflow (exit, release, discharge, go over, etc.) from the accumulation chamber (9). The descent assembly (15), which may take on various shapes and forms, as will be explained in greater detail hereinbelow, is intended for receiving the fluid flow (7) coming from the accumulation chamber (9) via the overflow interface (1 1 ), and for allowing said fluid flow (7) to descend to at least one lower height (13b) and preferably a plurality or a "cascade" of such lower heights 13b), the descent assembly (15) being configured so that residual flocculating agent from the fluid flow (7) is thereby additionally mixed or reacted with mature fine tailings from said fluid flow (7) when the fluid flow (7) is travelling down such a descent assembly (15) from an upper region (17a) to a lower region (17b), the descent assembly (15) being further configured for preventing overshearing of the flocculated mature fine tailings prior to depositing into the deposition cell.

As mentioned earlier, the descent assembly (15) may take on various suitable embodiments in order to provide the structural and functional benefits of the present invention. Indeed, referring to the general embodiment exemplified in Figures 1-29, the descent assembly (15) may comprise a cascading assembly (15i) having at least one step (19) and at least one corresponding riser (21 ), for providing a cascading effect to the fluid flow (7) trickling down said cascading assembly (15i) so as to additionally and gently mix the mature fine tailings with any remaining residual flocculating agent in the fluid flow, and/or for further promoting flocculation of the already flocculated mature fine tailings in the fluid flow, without causing overshearing prior to deposition, which is advantageous for MFT drying purposes, etc.

Indeed, because an objective of the present invention is to provide mixing of unreacted flocculating agent (i.e. polymer, etc.) while minimizing additional shear forces on the existing mixed material, the provision of a cascading assembly (15i) with components being adjustable for different types of fluid flows, different types of mature fine tailings to be treated, and/or other considerations, provides a simple, yet effective solution that enables to overcome various problems associated with conventional techniques. According to a preferred aspect of the present invention, the at least one step (19) of the cascading assembly (15i), is wider than the inlet (5), so as to namely slowdown the fluid flow (7) as it passes over each step ( 9) of the deposition device (1 ) so as to help minimize unwanted shear forces. Indeed, because the cascade box opens the flow onto steps (19) which are preferably far wider than the feed pipe (67) itself, velocity through the cascade box is substantially lower than what the fluid would normally see going through an in-line static mixer of the same feed pipe size. As a result, fluid shear forces are minimized as the flow passes over the descent assembly (15), which in the case of the main preferred embodiment exemplified in Figures 1 -29, consists of a series of steps (19) and corresponding risers (21 ). Preferably also, and as can be easily understood by a person skilled in the art, in view of the present description and the accompanying drawings, each step (19) and each riser (21 ) is configured to be adjustable, or at the very least interchangeable. More specifically, and as will be explained in greater detail hereinbelow, each step (19) may be adjustable in length, and adjustable in width, and similarly, each riser (21 ) may also be adjustable in height, as well as adjustable in width.

Indeed, although the preferred embodiments of the cascading assembly (15i) exemplified in Figures 1 -29 illustrate variants of the present deposition device (1 ) where each step (19) has a width substantially equal to that of a corresponding adjacent riser (21 ), it is worth mentioning that depending on the particular applications for which the deposition device (1 ) is intended for, the desired end results and other considerations, each subsequent step (19) could have a shape and a dimension being different from that of a preceding step (19), in that each subsequent step (19) could have, for example, a width or a length being different from that of a preceding step (19), in order to further slowdown a fluid flow (7) travelling down the cascading assembly (15i). Similar modifications could also be made to a given riser (21 ) with respect to a subsequent or a preceding riser (21 ), so as to adjustably and selectively vary the height of "fall" from one riser (21 ) to another. According to a particular embodiment of the present invention, each riser (21 ) is defined by a corresponding partitioning plate (23) which is preferably intended to be removably mountable onto a pair of opposite side walls (25a,25b) of the deposition device, each slot (27) being defined by a pair of guides (27a, 27b), as can be easily understood when referring to Figures 1 and 16-18, each partitioning plate (23) preferably extending in a substantially traverse manner with respect to the fluid flow (7) travelling down the cascading assembly (15i), as better shown in Figure 1 , for example. However, it is worth mentioning that although the partitioning plates (23) shown in the accompanying drawings extend in a substantially traverse manner with respect to the fluid flow (7), that is, in a substantially traverse manner with respect to a longitudinal axis (51 ) of the deposition device (1 ), the partitioning plates (23) may be configured so as to be extendable at a given suitable angle with respect to the fluid flow (7), or at the very least, with respect to the longitudinal axis (51 ) of the cascading assembly (15i), if deemed appropriate, depending on the desired end effects intended with the deposition device (1 ), as apparent to a person skilled in the art. In such a case, instead of having a given partitioning plate (23) being slidably insertable into opposite slots (27) of the side walls (25a, 25b) of the device (1 ), then either the side edges of the partitioning plates (23) or the corresponding slots (27) could be modified so that a first side edge of the partitioning plate (23) would be removably insertable into a first given slot (27) on a first given side wall (25a, 25b), and the opposite side edge of the same partitioning plate (23) would be removably insertable into a second slot (27) being at an angle on the opposite side wall (25b, 25a), that is, not oppositely positioned, with respect to the first slot (27). In such a case, the kit to be used with the present deposition device (1 ) could be provided with a suitable number of different partitioning plates (23) which could be interchanged, placed and displaced at different locations of the deposition device (1 ) in order to provide different operating configurations and capabilities for said deposition device (1 ). It is worth mentioning however that various other suitable means and dispositions are intended with the present invention so that the partitioning plates (23) may be positioned either substantially perpendicular to the longitudinal axis of the deposition device (1 ), or at an angle with respect thereto, depending on the particular applications and the desired end results intended with the deposition device (1 ), as apparent to a person skilled in the art.

In either case, each partitioning plate (23) preferably comprises a reinforcement component, such as an angle bar, as better shown in Figures 16 and 17, for providing structural reinforcement to the partitioning plate (23) in order to ensure that the partitioning plate (23) remains in a substantially rectilinear and un- deformed configuration. It is worth mentioning, as can also be easily understood by a person skilled in the art, that other suitable reinforcement components (ribs, flanges, etc.) could be used and mounted onto the partitioning plate (23) in order to provide such structural reinforcement.

Referring back to Figure 1 , there is shown how according to this particular embodiment of the present invention, the overflow interface (11 ) simply consists of the top edge (31 ) of an uppermost riser, and as will be explained in greater detail hereinbelow, the uppermost riser (21 ) may be either a corresponding partitioning plate (23), or an integrated riser (21b) provided by a base (33) portion of the deposition device (1 ). Indeed, according to a preferred embodiment, the cascading assembly (15i) is contained within a housing (25) having at least one side wall (25a,25b,25c), and a corresponding base (33), as can be easily understood when referring to Figures 1-9. More specifically, and according to the embodiment shown, the housing (25) preferably comprises a pair of opposite side walls (25a, 25b), and a rear end wall (25c), as well as a corresponding base (33) with integrated components which are securely mounted (ex. welded, bolted, etc.) onto the housing (25) in order to form the structural framework of the deposition device (1 ). Although the following components are not absolutely necessary for a minimal and proper operation of the present deposition device (1 ), the base (33) of the housing (25) preferably comprises at least one integrated step (19b) and at least one corresponding integrated riser (21 b), so as to minimally provide at least one step (19) and at least one riser (21 ) to the deposition device (1 ), for a minimal cascading effect, should no partitioning plates (23) be used, as can be easily understood by a person skilled in the art. However, as shown in Figures 1-29, these particular embodiments of the present invention intend to have at least one partitioning plate (23) being removably extendable across at least one integrated step (19b) of the base (33) of the housing, and preferably also, said at least one partitioning plate (23) is intended to extend along a distal edge of each integrated step (19b). However, it is worth mentioning also, that the present invention is not necessarily limited to the presence of such integrated steps (19b) or risers (21 b) provided by the base (33) of the housing, and that even in such an event, the present deposition device (1 ) is not limited to the presence of a single partitioning plate (23) per integrated step (19b).

Indeed, various other alternatives of the present invention may include a plurality of different partitioning plates (23) being removably extendable across a same integrated step (19b) of the base (33) for selectively defining a plurality of corresponding sub-steps along said same integrated step (19b). For example, when referring to Figure 1 , one could easily understand that instead of having a single pair of slots (27) disposed at the distal end of the uppermost integrated step (19b) of the base (33) of the housing (25), that a suitable number of corresponding slots (27) may be provided between said distal edge of such integrated step (19b) and the uppermost riser (21 ) shown so as to be capable of receiving either one, or a plurality of intermediate partitioning walls (23), which would define corresponding sub-chambers into which the fluid flow (7) may accumulate, rise, and then overflow onto a subsequent sub-chamber downstream (progressive cascading effect, etc.). Moreover, it could also be easily understood that an upper surface of each sub- chamber would define a corresponding liquid sub-step (19) for the system.

Indeed, when referring to the accumulation chamber (9) shown in Figure 1 for example, a person skilled in the art may appreciate that although a first step (19) is not structurally defined by a corresponding physical component, the upper fluid surface of the fluid flow (7) accumulated therein, and which overflows over the top edge (31 ) of the uppermost first physical riser (21 ) could be considered as being the very "first" step (19) of the cascading effect provided by the deposition device (1 ). Furthermore, according to the embodiment exemplified, the accumulation chamber (9) is defined within the housing (25) adjacent to the uppermost riser (21 ) of the deposition device (1 ), as briefly explained earlier, but it is worth mentioning also that other suitable accumulation chambers (9), such as a vertical pipe (55), or any other suitable structure where the fluid flow (7) can be substantially reduced in terms of velocity, when received from the inlet (5), and accumulated up to a desired starting height, from which a cascading effect can be undertaken, could also be appropriate according to the present invention. Moreover, the inlet (5) of the deposition device (1 ) is preferably provided with a flange connection (35) for removably connecting the inlet (5) to a source of fluid flow (7), such a pressurized in-line feed coming from a corresponding pipeline, or any other suitable source of fluid flow (7), as apparent to a person skilled in the art. As can be easily understood by a person skilled in the art, the flange connection (35) at the bottom of the cascade box provides the easiest entry point, and although different variations of the designs could have the feed pipe entering the top of the cascade box, as exemplified in Figures 25-29, this would require additional pipe and fittings.

The present deposition device (1 ) is preferably manufactured to be structurally rigid, and to be able to withstand the different loads and parameters in cause, and if need may be, may be provided with at least one reinforcement component (37), such as a structural crossbar, or any other suitable component which could provide structural rigidity to the overall housing structure of the deposition device (1 ), as apparent to a person skilled in the art. Similarly, the deposition device (1 ), or at the very least, its housing (25), preferably comprises at least one lifting component (39), such a lifting lug or corresponding bar assembly, as exemplified in Figures 1 , 2, 4, and 10-14, for allowing the deposition device (1 ) to be conveniently raised and carried over to another location, for corresponding operation. Alternatively, or in addition thereto, the deposition device (1 ) could also be provided with a skid base (41 ), as better shown in Figures 25-28, for allowing the deposition device (1 ) to be dragged from one location to another, as also apparent to a person skilled in the art. Indeed, the skid base (41 ) allows for the cascade box to be dragged around on site with ease which is required when using a single cascade box for multiple deposition cells. Alternatively, the lifting lugs can also be used at the top of the box to lift and move it as needed, instead of dragging. This is likely a most optimal way of transport, as can be easily understood by a person skilled in the art.

Referring now to the second main preferred embodiment of the present deposition device (1 ), as exemplified in Figures 30-48, there is shown how the descent assembly (15) may consist of a ramp assembly (15ii) having a top portion (43) and a bottom portion (45), the ramp assembly (15ii) having a ramp (47) being provided with at least one ridge (49) for additional mixing of the mature fine tailings with residual flocculating agent as the fluid flow (7) travels down the ramp (47) and corresponding ridges (49).

As can be easily understood, each ridge (49) may be disposed in a substantially traverse manner with respect to a longitudinal axis (51 ) of the ramp (47), but for certain applications, it might be more advantageous to have each ridge (49) being disposed at an angle with respect to said longitudinal axis (51 ). According to a preferred embodiment of the present invention, as better shown in Figures 30 and 33, the ramp (47) comprises a plurality of pairs of ridges (49) disposed crossways with respect to the ramp (47), and each ridge (49) can simply be defined by an angle stitch welded onto the ramp. It is worth mentioning also, as can be easily understood by a person skilled in the art, that other suitable dispositions, geometric configurations, components to be used for defining the ridges (49), are intended according to the present invention. For example, the expression "ridge" (49) is not intended to be interpreted in a restrictive way (i.e. protruding, etc.), and may include a given "recess" with which the fluid flow (7) may operate, in order to obtain desired end results. Indeed, instead of having corresponding ridges (49), one could provide a plurality of corresponding longitudinal recesses disposed about the ramp (47) where fluid flow (7) traveling down said ramp (47) would cooperate with such recesses which would provide the mixing of flocculated MFT with the polymer without overshearing, etc.

Figures 44-48 exemplify how the ramp assembly (15ii) according to a preferred embodiment of the present invention is tapered, the bottom portion (45) being wider than the top portion (43), namely so as to further reduce the flow velocity of the fluid flow (7), so as to provide an ideal mixing of un-reacted flocculating agent with the mature fine tailings while minimizing additional shear forces on the existing mixed material, as explained earlier. Preferably, the ramp assembly (15ii) is provided with a pair of containment walls (53) for containing the fluid flow (7) above the ramp, and between said containment walls (53), as better shown in Figures 44 and 47. However, as can be easily understood by a person skilled in the art, other suitable dispositions could be used for guiding the fluid flow (7) down along the ramp assembly (15ii).

According to this main second preferred embodiment of the deposition device (1 ), the accumulation chamber (9) is preferably a vertical pipe (55), as exemplified in Figures 30-38, the vertical pipe (55) having a diameter which is bigger than the diameter of its corresponding inlet (5). Preferably also, the top portion (43) of the ramp assembly (15ii) is removably connectable to the overflow interface (11 ) of the device (1 ), and such an overflow surface (11 ) is provided by an upper cut-out portion (57) of the vertical pipe (55), the upper cut-out portion (57) of the vertical pipe (55) being preferably provided with a spill box (59), as better shown in Figures 39-43. Preferably also, the spill box (59) comprises a pin (61 ), and a top portion (43) of the ramp assembly (15ii) comprises a corresponding hole (63), said hole (63) being insertable about the pin (61 ) for removably connecting the ramp assembly (15ii) onto the spill box (59), as can be understood when referring to Figures 30-33 and 39-46. Preferably also, the spill box (59) may further comprise a bottom abutment flange (65) for abutting against a peripheral surface of the vertical pipe (55) when the spill box (59) is mounted onto the upper cut-out portion (57) of the vertical pipe (55), for providing additional stability to the overall design of the deposition device (1 ). As can be easily understood by a person skilled in the art, aside from the components that are intended to be removably connectable onto one another, other suitable components of the deposition device (1 ) according to this particular embodiment could be suitably connected onto one another, via appropriate affixing means, such as welding, bolting, and the like.

The inlet (5) of the deposition device (1 ) according to this particular embodiment is preferably provided on a bottom portion (45) of the vertical pipe and provided by a feed pipe (67) mountable to said bottom portion (45) of the vertical pipe (55), the feed pipe (67) being fluidly connected to an inside portion of the vertical pipe (55) for feeding the vertical pipe (55) with fluid flow (7), and the feed pipe (67) being further fluidly connectable to a pipeline carrying the fluid flow (7). As may be appreciated, the bottom portion (45) of the vertical pipe (55) is preferably provided with at least one support (71 ), for providing a corresponding support to the overall deposition device (1 ), and according to the embodiment illustrated in the accompanying drawings, the at least one support (71 ) preferably comprises at least one supporting pipe (71 ), and preferably, three such supporting pipes (71 ) disposed in an equally spaced manner about the vertical pipe (55) along with the feed pipe (67). However, it is worth mentioning that other suitable means could be used for providing a corresponding support (71 ) to the vertical pipe (55), and thus to the slide deposition device (1 ), such as, for example, a corresponding plate, whether rectangular, circular or the like, which could be welded onto a bottom end of the vertical pipe (55). According to the embodiment illustrated in the accompanying drawings, each supporting pipe (71 ) which is preferably welded on to a bottom portion of the vertical pipe (55) is closed ended, so that no fluid flow (7) enters into any of the supporting pipes (71 ), therefore, a fluid connection is only preferably provided between the feed pipe (67) and the inside portion of the vertical pipe (55).

It may now be better appreciated that various different types of embodiments may be used for the different components and features of the present invention. For example, when referring to the third main preferred embodiment of the deposition device (1 ) illustrated in Figures 49-51 for example, there is shown how the accumulation chamber (9) may consist of a vertical pipe (55) and where the overflow interface (11 ) may simply consist of at least one aperture (73) defined about the vertical pipe (55), at suitable locations around said vertical pipe (55). More specifically, according to this embodiment, there is a plurality of apertures (73) at different heights, levels, offsets and angles of the vertical pipe (55), and preferably, there is a given set of apertures (73) for each level, so that, a minimal amount of two sets of apertures (73a, 73b) are required for carrying out a corresponding descent assembly (15), the first set being lower than the second set, and spaced apart such that fluid flow (7) is spilled out of the first set until mature accumulates above the first set sufficient to block the first set of apertures (73a) and cause the fluid flow (7) to flow upward the vertical pipe to the second set to be spilled out from said second set of apertures (73b), as can be easily understood by a person skilled in the art.

Therefore, one may now better appreciate that, according to the present invention, the descent assembly (15), corresponding structural and functional features, and resulting advantages, may consist of different alternatives, depending on the particular applications for which the present deposition device (1 ) is intended for, and the desired end results, as well as the degree of sophistication with which the mature fine tailings is to be treated, and the adaptability and/or the adjustability of the deposition device (1 ) being desired, as apparent to a person skilled in the art. According to the present invention, the deposition device (1 ) and corresponding parts are preferably made of substantially rigid materials, such as metallic materials (stainless steel, etc.), hardened polymers, composite materials, and/or the like, whereas other components thereof according to the present invention, in order to achieve the resulting advantages briefly discussed herein, may preferably be made of a suitably malleable and resilient material, such as a polymeric material (plastic, rubber, etc.), and/or the like, depending on the particular applications for which the deposition device (1 ) and resulting pipeline, fitting or deposition cell are intended for and the different parameters in cause, as apparent to a person skilled in the art.

It may now also be better appreciated how the present invention is a substantial improvement over the prior art in that, by virtue of its design and components, the deposition device (1 ) is simple and easy to use, as well as simple and easy to manufacture and/or assemble, and provide for a much more simple and cost effective manner of processing MFT, namely in order to recover flocculent agent not having been used and/or in order to aid in the water release of the flocculated mature fine tailings before deposition, for improving MFT drying purposes, etc.

Indeed, it is well known in the art that flocculated MFT is typically fed into a deposition cell via a pipeline. Very often, extra mixing of the fluid is required to bring the material to the optimal point for water release and subsequent drying time, Instead of having typical in-line mixing devices which introduce high amounts of shear force which in turn break up the flocculated MFT in their attempt to provide mixing, which is disadvantageous for obvious reasons known in the art, the present deposition device (1 ), such as for example, as cascade box, is placed at the head end of the drying cell with the feed pipe entering the lower back side of the box, in order to overcome several of the disadvantages associated with the prior art. Typically, and as explained herein, fluid fills the back chamber of the box thus elevating the fluid to the first cascade step, which is approximately six feet in height, the fluid then, by force of gravity, spills over a series of steps set to a predetermined height. As the fluid passes over each step, gentle mixing of the fluid is achieved until it flows out of the bottom and into the deposition cell.

Thus, the present deposition method and corresponding deposition devices (1 ) provide an ideal balance when mixing un-reacted polymer with mature fine tailings while minimizing additional shear forces on the existing mixed material. Tests having been carried out have shown to provide an improved mixing of flocculated MFT while minimizing shear forces. This is believed to be due to the design of the deposition device (1 ) (for example, the cascade box, etc.) which opens the flow to atmosphere and allows the fluid to flow over a series of steps (19) by force of gravity. This is a much more different approach than what is done with a typical mixer which is done in-line and under pressure at much higher velocities. In contrast, the present invention not only enables for a gentle mixing while minimizing shear forces, but after the last step (19) in the cascade box, the flocculated MFT flows directly into the deposition cell, helping to control flow into the cell and also to avoid high velocity discharges which would normally add more shear forces and potential safety hazards.

The present invention is also advantageous in that because according to a given embodiment, namely the cascade box, the deposition device (1 ) opens the flow onto steps (19) which are far wider than the feed pipe (67) itself, velocity through the cascade box is substantially lower than what the fluid would normally see going through an in-line static mixer of the same feed pipe size. As a result and as previously explained, fluid shear forces are minimized as the flow passes over the descent assembly (15), which according to the embodiments illustrated in Figures 1- 29 for example, take the form of steps (19) in a cascading box. Because the material will have the proper mixing and the flocculation is optimized, the deposition is set up for maximum water release and subsequent minimal drying time, one of the key performance indicators for tailings reduction operations. The present invention is also advantageous in that by virtue of its design and components, the deposition device (1 ) enables excess and un-mixed polymer (due to inefficient injection into the fluid flow, etc.), to be re-introduced into the stream thus creating the greatest potential for MFT drying. The present invention is also advantageous in that, as previously explained hereinabove, the deposition device (1 ) comprises components and means for implementing some adjustability in the number of steps (19) and risers (21 ) for a given scenario, and also for varying the spatial and dimensional characteristics of these steps (19) and risers (21 ), as explained earlier. For example, if only minimal mixing is required, then one can only use a single step (19), whereas if for a given fluid, due to process parameters, this requires a large amount of mixing, then one could use several or all of the steps (19) attainable or possible with the present deposition device (1 ), for obtaining maximum mixing.

As also briefly outlined above, the present invention is also advantageous in that the deposition device (1 ) provides mobility, being able to be picked up and moved around for transport or drainage purposes via its lifting components (39), or skid base (41 ), which is always very beneficial for operations and maintenance staff. The present invention is also advantageous in that the feed connection point, which is preferably a flange connection (35) at the bottom of the cascade box for example, provides an easy connection, particularly for tailings reductions operations where assets are continually being relocated. The width of the steps (19) also ensures that this lowers the velocity of the fluid and provides a gentle cascading effect where fluid shear is minimized. The fact that the steps (19) may be removable, in the event that the steps (19) are too high, or that a suitable number of steps (19) need to be changed, it is also advantageous in that the steps (19) and risers (21 ) can be removed and replaced with different types of steps (19) and risers (21 ) if deemed necessary, or replaced by another suitable number of steps (19) and/or risers (21 ), as explained earlier. Furthermore, it is worth mentioning that if need may be, the deposition device (1 ) may be configured so as to be provided with proper drainage means for allowing remaining fluid flow (7) inside the deposition device (1 ) to be evacuated. For example, the embodiment of the deposition device (1 ) illustrated in Figure 1 , that is, the cascade box, may be simply tilted about 90 degrees forward by a loader using the lifting lugs and a sling in order to drain the fluid out of the front, for example. Alternatively, or in addition thereto, the system could also be modified so as to add a large drain on the feed line just before entering the box. Another solution could simply involve an access hatch near the bottom that would offer a large opening for fluid to drain. Yet another solution would be to have at least one drainage hole (23a) on a bottom portion of each partitioning plate (23), as exemplified in Figure 17 for example, so that if no new feed of fluid flow (7) is brought to the deposition device (1 ), then any remaining fluid flow (7) inside the deposition device (1 ) could drain naturally by gravity by passing through the drainage hole (23a) of each partitioning plate (23), as can be easily understood by a person skilled in the art.

Of course, numerous modifications could be made to the above-described embodiments without departing from the scope of the invention, as defined in the appended claims.