DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
Information Disclosure Statement
The information disclosure statements (IDS) submitted on 21 October 2025 has been received and considered by the examiner.
Specification
Applicant’s acknowledgement of the use of trademarks in the specification has been received. Upon further consideration, generic terminology describing GEOTUBE® has been identified in the specification as filed ([0061]) and the prior objection is withdrawn.
Claim Amendments
Applicant’s amendments to the claims and the cancellation of claims 3 and 6 in the reply filed 21 October 2025 are acknowledged. These amendments overcome the prior objections and rejections under 35 USC § 112(b), which are withdrawn.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 2, and 29-44 are rejected under 35 U.S.C. 103 as being unpatentable over Laudal (“Evaluation Of Rare Earth Element Extraction From North Dakota Coal-Related Feed Stocks”, PhD Thesis, University of North Dakota, 2017) in view of Zhang and Honaker (Internat. J. Coal Geol. 195 (2018) 189-199, hereinafter “Zhang”) .
Regarding claim 1, Laudal teaches the leaching of rare earth metals from 60-gram samples of Hagel B coal into 125 mL of sulfuric acid (p. 125-126). Table 22 (page 139) discloses the quantities of elements that have been leached into the acid solution, thereby forming a pregnant leach solution. These quantities have been reproduced in Table A (below). Based on the size of the coal sample (60 g), the concentration of elements in the coal (Table A, columns 1 and 2) the volume of the solution (125 mL) and the extraction efficiency of each element (Table A, column 4), the concentrations of the various elements in the leachate are calculated (Table A, column 6). These data show that the leachate solution of Laudal comprises lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium, wherein the aggregate concentration of thorium and uranium is less than 1 mg/L (0.2 mg/L), wherein cobalt is present in an amount of 17.6 mg/L, which lies just outside the instantly claimed range of from 20 mg/L to 30 mg/L, and wherein the total rare earth concentration is 14 mg/L.
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Table A. Calculated concentrations in leachate obtained by Laudal from data presented in Table 22 of Laudal.
Laudal also discloses a pregnant leach solution generated from Harman-Hansen coal with both higher cobalt concentrations and higher total rare earth concentrations (406 mg/L and 238 mg/L, respectively, as calculated from the data in Table 22 of Laudal). These results are consistent with Laudal’s observation that different coals have different elemental composition (p. 138, ¶ 2), including different levels of rare earth elements (Fig. 31, 34, 51, and 52).
Laudal therefore teaches that their method is able to generate pregnant leach solutions with a wide range of concentrations of both cobalt and total rare earth elements, including over concentration ranges that encompass those instantly claimed.
Laudal also teaches that solution with higher rare earth concentrations have greater value and incur less additional costs (REE concentration is a major factor in measuring the success and viability of the proposed system, as a higher concentration will decrease costs of downstream purification; Appendix D, Section 4.2).
Therefore, it would have been obvious to one of ordinary skill in the art to apply the leaching method of Laudal to a variety of different coals, including ones that would generate pregnant leach solutions having cobalt and total rare earth concentrations in the instantly claimed ranges. One of ordinary skill in the art would have been motivated to do so in order to extract the valuable rare earth elements at high concentrations.
It is further noted that, generally, differences in concentration will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration is critical. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." See MPEP 2144.05 and In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). The instantly claimed concentrations of cobalt and total rare earths are therefore considered an obvious variation and/or routine optimization of the concentrations disclosed by Laudal.
Laudal does not explicitly teach a pregnant leach solution where iron is present at concentrations less than or equal to 15 mg/L. However, Laudal does teach that removal of iron from the leachate is an important goal to increase monetization value of the rare earth extracts (Chapter 6, p. 156-160), and that methods to remove iron include pH adjustment and selective precipitation from the leachate (p. 160, ¶ 1 and Fig. 82), gravity concentration pre-treatment (p. 157, ¶ 2), and an air oxidation process (p. 160, ¶ 1 and Appendix D, p. 17-18).
Therefore, it would have been obvious to one of ordinary skill in the art to apply at least one of these techniques in order to minimize the iron concentration in the PLS solution, including into the instantly claimed range of less than 15 mg/L. One of ordinary skill in the art would have been motivated to do so in order to increase the value of the leachate by removing unwanted impurities to the greatest extent possible.
It is noted that the courts have stated where the claimed ranges “overlap or lie inside the ranges disclosed by the prior art” and even when the claimed ranges and prior art ranges do not overlap but are close enough that one skilled in the art would have expected them to have similar properties, a prima facie case of obviousness exists (see In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); Titanium Metals Corp. of America v. Banner, 778 F2d 775. 227 USPQ 773 (Fed. Cir. 1985) (see MPEP 2144.05.01). Therefore, the claimed range of iron concentrations of less than 15 mg/L merely represents an obvious variant and/or routine optimization of the solutions taught by Laudal where iron concentration is reduced by various methods.
While Laudal does teach pH adjustment to precipitate iron impurities (p. 157, ¶ 2 and p. 160, ¶ 1), Laudal does not specifically teach a pregnant leach solution with a pH from 2.8 to 3.0.
However, like Laudal, Zhang also teaches that altering the pH of a leachate solution can be used to selectively precipitate different impurities from rare earth leachates (abstract). Zhang further teaches that raising the pH of a leachate to 3.0 can remove >95% of the iron from solution (p. 194, Section 3.4), and that raising the pH further may causes additional loss of rare earth ions (p. 195, ¶ 1, Table 3 and Fig. 9b).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to increase the pH of the solutions obtained by Laudal to 3.0, thereby removing nearly all of the iron, as taught by Zhang. One of ordinary skill in the art would have been motivated to do so in order to decrease the iron concentration and therefore increase the monetary value of the extracts, as suggested by Laudal.
Regarding claims 2 and 29-44, the concentrations of the rare earth elements disclosed by Laudal teach all the additional limitations recited in claims 2 and 29-44 (Table A, above).
Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13.
The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer.
Claims 1-2 and 29-44 are rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1, 3-14, and 18-19 of U.S. Patent No. 10,954,582 B1 (hereinafter “the ‘582 patent”) in view of Laudal.
Claims 1-2 and 29-44 are also provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claim 27-43 of copending Application No. 17/706,584 (hereinafter, “the ‘584 application”) in view of Laudal.
Claim 1 of the ‘582 patent and claim 42 of the ‘584 application each describe a method of extracting rare-earth elements into a pregnant leach solution that is essentially free of solids. However, neither claim 1 of the ‘582 patent nor claim 42 of the ‘584 application teach the composition of the resulting pregnant leach solution.
However, Laudal teaches that metals leached from different coals will contain the requisite high concentrations of the rare-earth elements and low concentrations of uranium, thorium and cobalt recited in claim 1 of the instant application (Table 22, page 139). Laudal also goes on to teach that pre-treatment of the coal to remove impurities is one option to reduce iron (p. 157) and that control of pH can also be used to remove impurities (p. 160, ¶ 1, Fig. 82 and Appendix A, p. 21). Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to try the method of the ‘582 patent and/or ‘584 application with the coals containing high REEs, as taught by Laudal to achieve the instantly claimed composition. One would have been motivated to do so in order to increase the value of the rare earth extracts by lowering the concentration of impurities in the leachates, as taught by Laudal (p. 156, section 6.1).
Any additional limitations of the ‘582 patent or the ‘584 Application are encompassed by the open claim language “comprising” found in the instant claims.
Response to Arguments
Applicant’s arguments, see pages 6-8 of the reply filed 21 October 2025, with respect to the rejections of claims 1-2 and 29-44 under 35 USC § 102 have been fully considered and are persuasive in that Laudal does not anticipate the composition of amended claim 1. Therefore, the prior rejection under 35 USC § 102 has been withdrawn. However, upon further consideration, a new grounds of rejection is made under 35 USC § 103 in view of Laudal and Zhang, as analyzed above.
Applicant's arguments, pages 8-11, with respect to obviousness have been fully considered but they are not persuasive.
Specifically, Applicant argues, page 10, that neither Laudal, Zhang, nor their combination disclose, teach, or suggest a solution having:
a pH from 2.8 to 3.0;
iron present at a concentration of less than or equal to 15 mg/L;
cobalt present in amount from 20 mg/L to 30 mg/L; and,
a total rare earth concentration of at least 25 mg/L.
However, as analyzed above, Zhang does suggest a leachate having a pH of 3.0, as it is noted that at this pH nearly all of the iron in the leachate will have been removed (p. 194, Section 3.4). Zhang also teaches that as pH increases, rare earth elements are also removed (Fig. 9b). Therefore it would have been obvious to one of ordinary skill in the art to raise the pH of the solution taught by Laudal to 3.0, or to optimize the pH by routine experimentation, in order to remove iron without removing too much of the rare earth elements present in the leachate.
It also would have been obvious to one or ordinary skill in the art to minimize the iron concentration, including to below 15 mg/L, by the selective precipitation procedure taught by Zhang (and suggested by Laudal, pl. 160), by the gravity concentration pre-treatment taught by Laudal (p. 157), and/or by the air oxidation process also suggested by Laudal (Appendix D, p. 17-18). One of ordinary skill in the art would have been motivated to do so in order to decrease the impurities and increase the value of the monetizable REE extracts.
As the desire to have a low iron concentration and the methods to achieve them are taught by the prior art, and because Applicant has shown nothing unexpected or critical about the instantly claimed range of less than 15 mg/L, pregnant leach solutions with an iron concentration in this range are therefore considered an obvious variant of those solutions explicitly disclosed in the prior art.
Regarding the cobalt concentration, Laudal discloses pregnant leach solutions with cobalt concentrations of both 17.6 mg/L and 406 mg/L, values that encompass the instantly claimed range of from 20 mg/L to 30 mg/L; furthermore one of ordinary skill in the art would expect to a complex solution with a cobalt concentration of 17.6 g/mL to be nearly indistinguishable in terms of its properties to one with a concentration of 20 mg/L. Again, Applicant has shown nothing unexpected or critical about the instantly claimed range of less than 20-30 mg/L, and therefore the claimed concentrations of cobalt are considered an obvious variant of those explicitly disclosed in the prior art.
Laudal also discloses pregnant leach solutions from coal leaching with total concentration of rare earth elements that are 14 and 238 mg/L, the latter of which lies in the instantly claimed range of greater than 25 mg/L. Laudal (Appendix D, Section 4.2) and Zhang (Section 3.6) also teach that higher concentrations of rare earth metals are associated with higher economic value. Therefore it would have been obvious to one of ordinary skill in the art to produce PLS with higher concentrations of REE by varying the material being leached, as taught possible by Laudal through the results obtained with Harman coal.
It is noted that the courts have stated where the claimed ranges “overlap or lie inside the ranges disclosed by the prior art” and even when the claimed ranges and prior art ranges do not overlap but are close enough that one skilled in the art would have expected them to have similar properties, a prima facie case of obviousness exists (see In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); Titanium Metals Corp. of America v. Banner, 778 F2d 775. 227 USPQ 773 (Fed. Cir. 1985) (see MPEP 2144.05.01).
The courts have also found that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). See MPEP 2144.05 II.
Therefore, the claimed ranges of concentrations recited in claim 1 merely represent an obvious variant and/or routine optimization of the values of the cited prior art.
Conclusion
Applicant's amendment necessitated the new grounds of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Nicholas A Piro whose telephone number is (571)272-6344. The examiner can normally be reached Mon-Fri, 8:00 am-5:00 pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Sally Merkling can be reached on (571) 272-6297. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/NICHOLAS A. PIRO/Assistant Examiner, Art Unit 1738
/PAUL A WARTALOWICZ/Primary Examiner, Art Unit 1735