US 2014/0225415 A1Published application

Traveling undercut solution mining systems and methods

AssigneeSolvay Chemicals, Inc.

InventorsRonald O. HUGHES, Jean-Paul DETOURNAY, Alain VANDENDOREN, Larry C. REFSDAL, Joseph A. VENDETTI, Michael C. MONTOYA

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Abstract

In-situ solution mining method of an ore bed, particularly containing trona, which comprises exposing to a solvent an ore region inside a borehole drilled in the ore, and dissolving a desired solute within the exposed region to provide a liquor and create a voided ‘undercut’, such undercutting making the ore susceptible to gravitational loading and crushing. Unexposed ore falls into the undercut by gravity without breaking the ore roof resulting in exposure of fresh ore to the solvent and in preventing solvent exposure to contaminating material near the roof. The desired solute is eventually dissolved away in the entire bed from its floor up to its roof. Solvent injection may be delivered through a conduit positioned inside the borehole, and may be moved by retracting or perforating the conduit. The method may employ an advancing undercut initiated up-dip and traveling down-dip, or a retreating undercut initiated down-dip and traveling up-dip.

Claims20

Dependent claims

A method for in situ undercut solution mining of a subterranean trona ore bed, said trona ore bed comprising a desired solute being selected from the group consisting of sodium sesquicarbonate, sodium carbonate, and sodium bicarbonate, said trona ore bed having a floor and a roof, the method comprising the following steps:

injecting a solvent comprising water through a plurality of unlined borehole portions, each of said unlined borehole portions comprising lateral side branches, each of said unlined borehole portions comprising a downhole end positioned within said trona ore bed and above said bed floor, each of said unlined borehole portion being horizontal or being slanted with one of its ends being at a higher elevation than the other end, in order to expose to the solvent a trona ore region within each of said unlined borehole portions or adjacent to said downhole end of said unlined borehole portions;
dissolving at least a portion of the desired solute, from said solvent-exposed trona ore region in a manner effective to form a liquor comprising said dissolved desired solute, and to further form an undercut above the bed floor, said undercut comprising at least a section of said unlined borehole portions which have been eroded by dissolution, wherein said lateral side branches of each of said unlined borehole portions favor the lateral widening of said undercut during solvent injection and dissolution;
repeating the solvent injection to dissolve additional desired solute from the trona ore thereby enriching the liquor in desired solute, and further in a manner effective to widen the undercut and to trigger the fracture of unexposed trona ore located above said undercut and the downward movement of fractured trona ore rubble by gravity into the undercut, thereby creating fresh surface area of trona ore available for solvent dissolution;
and
flowing the liquor towards a subterranean collection zone in order to pass said liquor to a terranean location.

2 more elements

injecting a solvent comprising water through a plurality of parallel unlined borehole portions, each of said unlined borehole portions comprising a downhole end positioned within said trona ore bed and above said bed floor, each of said unlined borehole portion being horizontal or being slanted with one of its ends being at a higher elevation than the other end, in order to expose to the solvent a trona ore region within each of said unlined borehole portions or adjacent to said downhole end of said unlined borehole portions, wherein said parallel unlined borehole portions are initially in fluid communication with each other by having a common borehole end which is connected by unlined curved sections to each of the parallel unlined boreholes;
dissolving at least a portion of the desired solute, from said solvent-exposed trona ore region in a manner effective to form a liquor comprising said dissolved desired solute, and to further form an undercut above the bed floor, said undercut comprising at least a section of said unlined borehole portions which have been eroded by dissolution;
repeating the solvent injection to dissolve additional desired solute from the trona ore thereby enriching the liquor in desired solute, and further in a manner effective to widen the undercut and to trigger the fracture of unexposed trona ore located above said undercut and the downward movement of fractured trona ore rubble by gravity into the undercut, thereby creating fresh surface area of trona ore available for solvent dissolution;
and
flowing the liquor towards a subterranean collection zone in order to pass said liquor to a terranean location.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/222,573Filed 21 Mar 2014
Priority: 1 Aug 2008
Published: 14 Aug 2014
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

E21B 43/283
Dissolving minerals other than hydrocarbons, e.g. by an alkaline or acid leaching agent: in association with a fracturing process
E21B 43/28
Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells: dissolving minerals other…
E21B 43/292
Obtaining a slurry of minerals, e.g. by using nozzles: using steerable or laterally extendable nozzles
E21C 37/00
Mining or quarrying: other methods or devices for dislodging with or without

Family

Application61/085,735Us provisional application · filed 1 Aug 2008
Application61/172,538Us provisional application · filed 24 Apr 2009
Application13/056,081Continuation · filed 26 Jan 2011
Application14/222,573Continuation
US 2011/0127825 A1Published application
US 8,678,513 B2Related patent
US 9,234,416 B2Related patent
US 2014/0225415 A1This patent

From the US filing history. Foreign family members aren’t listed.