| Document and Entity Information | Feb. 04, 2022 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Feb. 4, 2022 |
| Entity File Number | 000-55402 |
| Entity Registrant Name | Rocky Mountain Industrials, Inc. |
| Entity Incorporation, State or Country Code | NV |
| Entity Tax Identification Number | 46-0750094 |
| Entity Address State Or Province | CO |
| Entity Address, Address Line One | 4601 DTC Blvd |
| Entity Address, Adress Line Two | Suite 130 |
| Entity Address, City or Town | Denver |
| Entity Address, Postal Zip Code | 80237 |
| City Area Code | 720 |
| Local Phone Number | 614-5213 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Entity Central Index Key | 0001556179 |
| Amendment Flag | false |
