Shaft Sinking Patents: Who Leads, Where the Gaps Are 2026
- 77.9% concentration. The top five assignees combine for 116 of the 149 records in scope — this is a field owned by a handful of specialist sinking contractors and equipment builders, not a broad industry.
- E21D dominates but E21B is close behind. 60.4% of records touch shaft and tunnel support (E21D), while 30.9% also carry earth and rock drilling claims (E21B), showing sinking method and drilling hardware are usually claimed together.
- Filing has cooled from its 2018 peak. Annual filings peaked at 10 in 2018; the 2026 count of 0 reflects the ~18-month publication lag rather than an actual stop in activity.
Top-5 share is the combined record count of the five largest assignees divided by all 149 records in scope (CR5), not by the ranked leaders only.
What the shaft sinking and shaft equipping patent record shows
Shaft sinking and shaft equipping covers the methods and machinery used to excavate, support and fit out vertical mine and well shafts: boring machines, ground freezing and advance grouting to control water inflow, mucking systems for spoil removal, and the guide and lining installation that follows the cut. The search underlying this page combines shaft sinking, shaft lining and shaft boring machine terms with the specific control techniques — ground freezing, advance grouting, mucking systems, guide installation, advance rate and water inflow control — that separate a working method claim from a general excavation patent.
149 published records fall within scope across the 2015 to 2026 coverage window. Ownership is unusually concentrated for a mechanical/civil engineering field: a small set of specialist sinking contractors, drilling equipment makers and oil-sands operators account for almost all of the activity, with the ranked leaders accounting for 99.3% of records between them.
Filing trend and technology composition
The dataset covers 149 published records from 2015 through the 2026-07-31 cut-off. Because publication typically lags filing by roughly 18 months, the most recent one to two years understate real filing activity.
A 2018 peak, then a decline consistent with publication lag
Annual filings ran at 5 in 2017 and rose to a peak of 10 in 2018. The apparent falloff toward 2026, ending at 0, is expected: recent filings have not yet cleared examination and publication, not evidence that sinking innovation has stopped.
Support and drilling classes carry the claim weight
E21D (shafts, tunnels and mine support) appears on 60.4% of the 149 records, and E21B (earth and rock drilling for wells) on 30.9% — the overlap reflects that shaft boring machines and their ground-control methods are typically claimed together. B66B (lifts and escalators, 22.8%) and E21F (mine safety and ventilation, 15.4%) form a second tier tied to shaft equipping and safety systems, while E02D, C09K, E04H and E21C each sit under 13% and mark narrower, more specialised claim territory.
Shares are the percentage of the 149 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Shaft Sinking and Shaft Equipping with Eureka
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Try EurekaThe most-cited records in shaft sinking and shaft equipping
US4646853A — Shaft boring machine and method
A shaft boring machine including a rotatable cutterwheel assembly with a horizontal axis mounted on a carriage having vertical travel. The carriage is mounted on a slewing base frame and rotates about the vertical axis of the machine. An excavating unit for muck removal is mounted opposite the cutterwheel on the slewing base frame and loads directly from the shaft bottom into a muck hopper. When the hopper is full, it is discharged into a hoist bucket which is hoisted to the surface. The machine is positioned in the shaft by upper and lower gripper systems, and walking cylinders between the two gripper rings advance the machine up or down the shaft.Filed by The Robbins Company, granted 1987-03-03. With 84 citations inside this corpus, it is the second most-cited record in scope and the most-cited full-machine (rather than downhole-method) design.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20080017416A1 | Method of drilling from a shaft for underground recovery of hydrocarbons | 149 |
| 2 | US4646853A | Shaft boring machine and method | 84 |
| 3 | US6375271B1 | Controlled foam injection method and means for fragmentation of hard compact rock and concrete | 44 |
| 4 | US6102484A | Controlled foam injection method and means for fragmentation of hard compact rock and concrete | 43 |
| 5 | US8127865B2 | Method of drilling from a shaft for underground recovery of hydrocarbons | 42 |
| 6 | US4494617A | Shaft boring machine | 39 |
| 7 | US4270876A | Method of lining a vertical mine shaft with concrete | 35 |
| 8 | US5232268A | Method of breaking a full face of rock for constructing shafts and tunnels | 29 |
| 9 | WO2011000037A1 | Forming a shaft for an underground mine | 28 |
| 10 | US4516633A | Blind shaft drilling | 22 |
Citation counts are measured within this searched corpus and favour older filings; treat them as a signal of influence on later filers, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns matter more than the raw counts: how tightly ownership is held, which classes carry the real claim density, and how citation weight sits with older downhole-drilling patents rather than newer equipping methods.
A field owned by a handful of specialists
The top five assignees combine for 116 of the 149 records in scope, and the top ten reach 99.3%. A new entrant is not filing into open ground held by dozens of competitors — it is filing directly against a small number of established sinking contractors and drilling-equipment builders.
Support and drilling claims are usually paired
E21D and E21B co-occur often enough that a shaft boring machine claim and its ground-control method are typically prosecuted together rather than separately. Filers who claim only the drilling hardware without the support method are leaving part of the value on the table relative to how incumbents file.
Influence sits with older downhole-drilling patents
The two most-cited records both address drilling from a shaft for underground hydrocarbon recovery, and the top mechanical shaft boring machine patent dates to 1987. High citation counts here mark foundational prior art that later filers had to design around, not current state of the art.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to shaft sinking and shaft equipping, with the prior art for and against each one.
Who holds the ground, and where activity has gone quiet
Ownership concentration and the co-filing pattern between two Australian sinking specialists point to a small, stable set of incumbents rather than a shifting competitive field.
One assignee holds more than a third of the field
The leading assignee's 55 records make it the single largest holder by a wide margin over the rest of the ranked list, well ahead of the fifth-place holder at 9 records.
The strongest co-assignee pair dominates joint filings
Of 10 identified co-assignee pairs, one pairing between two Australian sinking-contractor entities accounts for 19 shared records — far ahead of the next pairs, which sit at 2 shared records each involving an oil-sands operator and named inventors.
Recent-year activity has gone quiet across the board
Every assignee tracked for recent-year momentum, including the field's leader, shows zero filings in the latest year. Given the roughly 18-month publication lag, this reads as a reporting gap rather than a genuine stop in R&D.
| Assignee | Recent year | YoY |
|---|---|---|
| Technological Resources Pty Ltd | 0 | — |
| TRIOMVIRI PTY LTD TRADING AS THE GROBLER PARTNERSHIP | 0 | — |
| RELBORGN PTY LTD | 0 | — |
| Master Sinkers Pty Ltd | 0 | — |
| HARRISON WESTERN A FLA | 0 | — |
| The Robbins Company | 0 | — |
| PI ENGINEERING INC | 0 | — |
| POWELL BEN WILLIAM | 0 | — |
Where to take this next
The dataset points to specific follow-up questions rather than a single conclusion — concentration at the top, a class mix weighted to support and drilling, and citation weight sitting on older downhole patents each suggest a different next step.
Map the leader's claim boundaries
With one assignee holding 55 of 149 records, understanding exactly which claim elements it controls is the first filter for any new shaft-equipping filing.
Explore assignee claim scope in EurekaCheck the under-claimed IPC branches
Classes like C09K and E04H sit well below the E21D/E21B core and may hold room for a narrower, defensible claim.
Run a white-space search in EurekaTrace citation chains from the most-cited records
The two highest-cited patents both concern drilling from a shaft for hydrocarbon recovery — tracing who cites them shows how the downhole-drilling lineage has been designed around.
Trace citation lineage in EurekaFrequently asked questions
Ownership in this dataset is highly concentrated: the top-ranked assignee alone holds 55 of the 149 records in scope, and the top five assignees together account for 77.9% of all records. The ranking covers 27 companies in total, with the fifth-place holder at 9 records and tenth place at only 5. This means a small number of specialist sinking contractors and drilling-equipment builders control most of the documented claim space, rather than activity being spread across the broader mining supply chain.
The core of the field sits in IPC class E21D, shafts, tunnels and mine support, which appears on 60.4% of the 149 records. E21B, earth and rock drilling for wells, is the next largest at 30.9%, reflecting how often shaft boring machinery and ground-control methods are claimed in the same filing. Secondary classes include B66B (lifts and escalators, 22.8%) for shaft equipping and hoisting, and E21F (mine safety and ventilation, 15.4%); because a single record can carry multiple classes, these shares add up to more than 100% of records.
The apparent decline is a data artefact, not a real slowdown. Patent publication typically lags the actual filing date by around 18 months, so records filed in 2025 and 2026 have largely not yet appeared in the published dataset. Filing activity peaked at 10 records in 2018, and later years should be read with that lag in mind rather than as a genuine drop-off in R&D.
US4646853A, assigned to The Robbins Company and granted in 1987, claims a shaft boring machine built around a rotatable cutterwheel on a vertically travelling carriage, a muck-handling unit that loads directly into a hoist bucket, and an upper/lower gripper system with walking cylinders that advances the machine along the shaft axis. Any new design that combines a rotating cutter, direct-to-hoist muck handling, and gripper-based self-advancement in a single vertical shaft machine sits close to this claim structure. With 84 citations inside this corpus, it is one of the most-referenced mechanical shaft boring designs, meaning later filers have generally had to design around its gripper-and-cutterwheel combination specifically.
The IPC classes with the lowest record shares in this dataset — C09K (materials for water inflow control and similar applications, 6.7%), E04H (specialised shaft-head structures, 6.0%) and E21C (mining and quarrying-adjacent excavation, 5.4%) — carry far fewer records than the dominant E21D and E21B combination. That gap suggests narrower opportunities in water-control materials, shaft-head structural design, and excavation methods that overlap with quarrying rather than pure shaft boring. These are not guaranteed open areas, but they are the branches least occupied relative to the rest of the field's filing density.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
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Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.