Prosecution Insights
Last updated: April 18, 2026
Application No. 17/784,970

PRETREATMENT METHOD FOR UTILIZATION OF COAL ASH LANDFILLED IN ASH PONDS

Non-Final OA §103
Filed
Jun 13, 2022
Examiner
KUMAR, KALYANAVENKA K
Art Unit
3653
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
National Institute Of Environmental Research
OA Round
4 (Non-Final)
73%
Grant Probability
Favorable
4-5
OA Rounds
3y 3m
To Grant
91%
With Interview

Examiner Intelligence

Grants 73% — above average
73%
Career Allow Rate
517 granted / 709 resolved
+20.9% vs TC avg
Strong +18% interview lift
Without
With
+17.9%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
30 currently pending
Career history
739
Total Applications
across all art units

Statute-Specific Performance

§101
0.9%
-39.1% vs TC avg
§103
54.2%
+14.2% vs TC avg
§102
22.7%
-17.3% vs TC avg
§112
14.8%
-25.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 709 resolved cases

Office Action

§103
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 . DETAILED ACTION Claim Rejections - 35 USC § 103 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 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. 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 of this title, 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. Claims 8, 9, and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Kang et al (KR 101565906) (Translation provided in IDS dated 9/25/2022) in view of Design Choice. Regarding claim 8, Kang discloses a method of obtaining a byproduct having increased purity of unburned carbon and amorphous compounds from coal pond ash, comprising: (a2) subjecting coal pond ash (page 3, lines 32- 36 and page 6, lines 1-4) to screening (page 2; claim 1, line 5 separated ash), flotation (page 2; claim 2, lines 2-4 flotation step), and recovery (page 2; claim 1, line 8); (a3) subjecting coal pond ash to screening, float-sink, grinding, flotation, and recovery; (a4) subjecting coal pond ash to screening, float-sink, magnetic separation, and recovery; (a5) mixing a byproduct obtained through screening, float-sink, primary magnetic separation, and grinding of coal pond ash with a residue obtained in step (a2) and then performing secondary magnetic separation and recovery; or (a6) subjecting a residue obtained in step (a5) to magnetic separation and recovery, wherein in step of screening, the coal pond ash is classified into coarse particles having a diameter of greater than 2.36 mm, intermediate particles having a diameter of 0.15-2.36 mm, and fine particles having a diameter of less than 0.15 mm, using standard sieves with grids of 0.15 mm and 2.36 mm; wherein step of flotation is performed at a pH of 7; wherein, step of float-sink is performed using a solution with a specific gravity of 2.2; and wherein, in step of magnetic separation, from a mixture of the residue obtained in step of flotation and the residue obtained in step of float-sink, a fine material containing high-purity Fe oxide is separated using a 0.1 T wet magnetic separator and then a fine material containing low- purity Fe oxide is separated using a 1.0T wet magnetic separator. Kang does not explicitly disclose the coal pond ash is classified into coarse particles having a diameter of greater than 2.36 mm, intermediate particles having a diameter of 0.15-2.36 mm, and fine particles having a diameter of less than 0.15 mm, using standard sieves with grids of 0.15 mm and 2.36 mm. However, before the time the invention was effectively filed, it would have been an obvious matter of design choice to a person of ordinary skill in the art before the effective filing date of the claimed invention with a reasonable expectation of success to separate ash in different size fractions because Applicant has not disclosed that the particle dimension provides an advantage, is used for a particular purpose, or solves a stated problem. One of ordinary skill in the art, furthermore, would have expected Kang, and applicant’s invention, to perform equally well with either particle dimension because both particle ranges would perform the same function of separating particles for the purpose of processing different particle sizes. Kang does not explicitly disclose step (a2) is performed at a pH of 7. However, before the time the invention was effectively filed, it would have been an obvious matter of design choice to a person of ordinary skill in the art before the effective filing date of the claimed invention with a reasonable expectation of success to flotation separation because Applicant has not disclosed that pH level for flotation provides an advantage, is used for a particular purpose, or solves a stated problem. One of ordinary skill in the art, furthermore, would have expected Kang in view of Bae, and applicant’s invention, to perform equally well with either pH level because both flotation separations would perform the same function of separating particles with flotation for the purpose of separating minerals. Furthermore, line 11 states ‘or’ at the end of the line indicating that only one of the steps a2 through a6 is performed. As such, the additionally limitations added by amendment regarding pH and float-sink are not required as step a2 is addressed above. Regarding claim 9, Kang discloses a method of obtaining a byproduct having increased efficiency of recovery of Fe oxide from coal pond ash, comprising: (b2) subjecting coal pond ash (page 3, lines 32- 36 and page 6, lines 1-4) to screening (page 2; claim 1, line 5 separated ash), flotation (page 2; claim 2, lines 2-4 flotation step), and recovery (page 2; claim 1, line 8); (b3) subjecting coal pond ash to screening, float-sink, and recovery; (b4) mixing a byproduct obtained through screening, float-sink, and grinding of coal pond ash with a residue obtained in step (b2) and then performing magnetic separation and recovery; or (b5) subjecting a residue obtained in step (b4) to magnetic separation and recovery, wherein in step of screening, the coal pond ash is classified into coarse particles having a diameter of greater than 2.36 mm, intermediate particles having a diameter of 0.15-2.36 mm, and fine particles having a diameter of less than 0.15 mm, using standard sieves with grids of 0.15 mm and 2.36 mm; wherein step of flotation is performed at a pH of 7; wherein step of float-sink is performed using a solution with a specific gravity of 2.2 wherein step of grinding is performed to have a size of less than 0.15 mm; and wherein, in step of magnetic separation, from a mixture of the residue obtained in step of flotation and the residue obtained in step of float-sink, a fine material containing high-purity Fe oxide is separated using a 0.1T wet magnetic separator and then a fine material containing low- purity Fe oxide is separated using a 1.0T wet magnetic separator. Kang does not explicitly disclose the coal pond ash is classified into coarse particles having a diameter of greater than 2.36 mm, intermediate particles having a diameter of 0.15-2.36 mm, and fine particles having a diameter of less than 0.15 mm, using standard sieves with grids of 0.15 mm and 2.36 mm. However, before the time the invention was effectively filed, it would have been an obvious matter of design choice to a person of ordinary skill in the art before the effective filing date of the claimed invention with a reasonable expectation of success to separate ash in different size fractions because Applicant has not disclosed that the particle dimension provides an advantage, is used for a particular purpose, or solves a stated problem. One of ordinary skill in the art, furthermore, would have expected Kang, and applicant’s invention, to perform equally well with either particle dimension because both particle ranges would perform the same function of separating particles for the purpose of processing different particle sizes. Furthermore, line 9 states ‘or’ at the end of the line indicating that only one of the steps b2 through b5 is performed. As such, the additionally limitations added by amendment regarding pH and float-sink are not required as step b2 is addressed above. Regarding claim 13, Kang discloses a method of obtaining a byproduct having increased strength from coal pond ash, comprising: (e1) subjecting coal pond ash composed of a mixture of fly ash and bottom ash (page 3, lines 32- 36 and page 6, lines 1-4) to screening, flotation (page 2; claim 2, lines 2-4 flotation step), and recovery (page 2; claim 1, lines 5 and 8); or (e2) subjecting coal pond ash to screening, float-sink, and recovery. Kang does not explicitly disclose the coal pond ash is classified into coarse particles having a diameter of greater than 2.36 mm, intermediate particles having a diameter of 0.15-2.36 mm, and fine particles having a diameter of less than 0.15 mm, using standard sieves with grids of 0.15 mm and 2.36 mm. However, before the time the invention was effectively filed, it would have been an obvious matter of design choice to a person of ordinary skill in the art before the effective filing date of the claimed invention with a reasonable expectation of success to separate ash in different size fractions because Applicant has not disclosed that the particle dimension provides an advantage, is used for a particular purpose, or solves a stated problem. One of ordinary skill in the art, furthermore, would have expected Kang, and applicant’s invention, to perform equally well with either particle dimension because both particle ranges would perform the same function of separating particles for the purpose of processing different particle sizes. Furthermore, line 4 states ‘or’ at the end of the line indicating that only one of the steps e1 through e2 is performed. As such, the additionally limitations added by amendment regarding pH and float-sink are not required as step e1 is addressed above. Allowable Subject Matter Claims 1, 5, and 7 are allowed. The following is an examiner’s statement of reasons for allowance: The closest prior art discloses a method of obtaining unburned carbon and Fe oxide from coal pond ash. The closest prior art does not disclose or make obvious wherein in step (d), from a mixture of the residue obtained in step (b) and the residue obtained in step (c), a fine material containing high-purity Fe oxide is separated using a 0.1T wet magnetic separator and then a fine material containing low-purity Fe oxide is separated using a 1.0T wet magnetic separator in conjunction with the other structures in claim 1. Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.” Response to Arguments Applicant's arguments filed 8/21/2025 have been fully considered but they are not persuasive. Rejection under USC 112 Regarding the rejection of claims 8 and 9, the USC 112 rejection has been withdrawn as the claims have been amended to include ‘or’ instead of ‘and’ as previously presented. A new rejection based on the ‘or’ limitation is shown above. Rejection under USC 103 Regarding Applicant’s argument,” Claims 8 and 9 as thus amended herein are patentably distinguished over Kang in view of Design Choice. See in this respect the Examiner's statement of reasons for allowance in paragraph 16 at page 7 of the Office Action, addressing the allowance of claims 1, 5, and 7, and discussing that "step (b) [flotation] is performed at a pH of 7" and that ‘float-sink is performed using a solution with a specific gravity of 2.2", as features that "[t]he closest prior art does not disclose or make obvious’,” the Examiner disagrees. The Examiner asserts that Kang discloses subjecting coal pond ash (page 3, lines 32- 36 and page 6, lines 1-4) to screening (page 2; claim 1, line 5 separated ash), flotation (page 2; claim 2, lines 2-4 flotation step), and recovery (page 2; claim 1, line 8) and includes the design choice analysis for the specific ranges and values of each of the steps. Furthermore, regarding claim 13, the rejection dated 9/2/2025 inadvertently omitted the rejection related to the amendment dated 8/21/2025. The rejection above has corrected the previous omission. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to Kalyanavenkateshware Kumar whose telephone number is (571)272-8102. The examiner can normally be reached on M-F 08:00-16:30. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Michael McCullough can be reached on 571-272-7805. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /K.K./Examiner, Art Unit 3653 /MICHAEL MCCULLOUGH/ Supervisory Patent Examiner, Art Unit 3653
Read full office action

Prosecution Timeline

Jun 13, 2022
Application Filed
Nov 26, 2024
Non-Final Rejection — §103
Mar 05, 2025
Response Filed
May 17, 2025
Final Rejection — §103
Jul 21, 2025
Response after Non-Final Action
Aug 21, 2025
Request for Continued Examination
Aug 25, 2025
Response after Non-Final Action
Aug 27, 2025
Non-Final Rejection — §103
Dec 02, 2025
Response Filed
Apr 02, 2026
Non-Final Rejection — §103 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12594582
SYSTEM FOR ANALYZING AND SORTING A MATERIAL PART
2y 5m to grant Granted Apr 07, 2026
Patent 12558709
SCRAP COLLECTION DEVICE
2y 5m to grant Granted Feb 24, 2026
Patent 12551901
SYSTEM AND METHOD FOR RECOVERING METAL FROM ASH
2y 5m to grant Granted Feb 17, 2026
Patent 12544788
METHOD FOR SEPARATING THE COMPONENTS OF A MIXTURE OF FIBERS AND GRANULES BY ELECTROSTATIC NEUTRALIZATION AND SCREENING, AND CORRESPONDING UNIT
2y 5m to grant Granted Feb 10, 2026
Patent 12528089
METHOD FOR THE REGENERATION OF THE MAGNETIC MATERIAL USED FOR THE MAGNETIC REMOVAL OF MICROPLASTICS FROM AQUEOUS MATRICES
2y 5m to grant Granted Jan 20, 2026
Study what changed to get past this examiner. Based on 5 most recent grants.

AI Strategy Recommendation

Get an AI-powered prosecution strategy using examiner precedents, rejection analysis, and claim mapping.
Powered by AI — typically takes 5-10 seconds

Prosecution Projections

4-5
Expected OA Rounds
73%
Grant Probability
91%
With Interview (+17.9%)
3y 3m
Median Time to Grant
High
PTA Risk
Based on 709 resolved cases by this examiner. Grant probability derived from career allow rate.

Sign in with your work email

Enter your email to receive a magic link. No password needed.

Personal email addresses (Gmail, Yahoo, etc.) are not accepted.

Free tier: 3 strategy analyses per month