Borehole 10X

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Borehole 10X (Shaft 29)
Greatest depth232ft (estimated)
CompanyDan Blankenship
Image Copyright (Used with permission)

Borehole 10X was started in the summer of 1970 and is approximately 55 meters (180 feet) northeast of the Money Pit.  Triton Alliance hired the Bowmaster Drilling Company, who employed a 15 cm (6 inch) rotary drill to bore down to a total depth of 70 metres (230 feet).  Bedrock was encountered at 55 metres (180 feet), and at 70 metres (230 feet) and a cavity was found. While this cavity has become famous for the contents thought to be contained within, it was not the only cavity found while drilling Borehole 10X though.  Two more cavities were passed through, above bedrock, on the way.  They were encountered at depths of 43 metres (140 feet), and 49 metres  (160 feet).  When Triton Alliance widened the borehole to allow people access to the depths, Borehole 10X officially became the 29th Shaft on Oak Island.

Initial drilling[edit]

Location: 181 feet east of #24 (2), by the door of the old Restall house.

Drilling Hole #10:

  • Started with a 9 inch rock bit and went very fast through overburden and glacial till.
  • Small cavity from 140 feet to 143 feet and another from 165 feet to 169 feet and hit bedrock at 185 feet of gypsum
  • Drove 10 feet into bedrock with the 9 inch bit and stopped at 195 feet at which point we put on the 6 inch rock bit in order to leave a shelf in case we hit a cavity, for our casing to seat into
  • Hit a cavity at 230 feet to 233 feet
  • Pulled the bit out and put on his 6 inch core barrel 22 feet long which is supposed to take a 3 inch core.
  • Only a few pieces of gypsum were there, and so we pulled out of the hole and went down to do hole #9.
10x hedden chappel.JPG

Drilling Hole #9:

  • Put down 124 feet of casing before it stopped and hung up.
  • Put the 6 inch rock drill inside and drilled to 150 feet.
  • The casing then went to 148 feet before it hung up again, at which time he again put the drill back down into the casing and drilled.
  • At this time Joe Stein came onto the site and was present. Bowmaster was using air and the return was very good.
  • I was collecting the return that was coming out and I noticed bits of rag and small pieces of metal
  • This metal and rags came up from about 166 feet to 175 feet.
  • It is very important to note at this time a lot of water was coming up and upon tasting it I discovered it was salt. 
  • We continued drilling down to 198 feet and then drove the casing to 178 feet.
  • While driving this, the last piece of casing broke off 14 feet below ground level.
  • Friday, the next day I used a backhoe and dug down and cut the casing. Not having a welder, I put a 16 foot long piece of 8 inch diameter casing over the 6 inch and back filled in preparation for Warnock-Hersey. Friday evening they came and unloaded gear and set up.
  • Saturday they came and started dropping 3 ½ inch casing inside Bowmaster’s 6 inch casing and it went easy to about 212 feet at which time they started drilling it down.
  • The drilling was hard at first and then eased up, breaking through of its own weight at about 218 feet
  • The 3.5 inch casing was then turned for about 1.5 inches into bedrock, which interesting enough was 237.5 feet. 
  • After the 3 ½ inch casing was seated, Warnock Hersey started coring with a 2 ½ inch core barrel 5 feet long. 


  • It was thought at this time that the metal was coming from the bottom of the hole and so we decided to blast.
  • We blasted and bailed out a total of 4 times at the bottom of the hole. It was during this time that we started getting clay in pieces and also pieces of gypsum rock. However no metal at all came out. I did get a large amount of cement-like material that later proved to be natural. We then terminated the drilling with Harold Verge and he pulled out.
  • We then started systematically to blast and bail at the bottom of the hole and worked our way up.
  • The blasting was done with two sticks of 2 inch by 8 inch of 75% dynamite using a cap for each stick and this was done every 2 feet and bailed out each time to 232 feet. The total height reached was 215 feet at which point we put a total of 5 sticks 2 inch by 8 inch.
  • After blasting we could hear the rocks falling in, about 4 times and dropped our measuring rock down and found that a total of 12 feet had piled at the bottom of the hole. This was after dark Saturday night and so nobody would get hurt we quit work and started to bail out Monday morning at which time only 6 feet was piled at the bottom of the hole, so the blasting done at the bottom had to be extensive.
  • We bailed the hole out again to 232 feet and not one piece of metal was found. It was then painfully plain that the metal came from higher up behind the casing and that driving the casing had effectively sealed it off as well as sealed the sand and rocks.

Steel casing[edit]

Installing 27 in Casing[edit]

  • Based on the artifacts pulled up during the drilling, and the believed free communication of seawater into 10x, Dan Blankenship was convinced that borehole 10 had something to do with the flood system and possibly contained treasure in the bottom cavity.
  • With the support of Triton Aliance, the Statesman Mining Company was hired to open borehole 10 to a diameter of 25inches. From this point forward, borehole 10 would be known as 10x. [1]It was during this phase of construction Stateman suggested that John Wayne narrate a documentary on the work going on on Oak Island, which is believed to have started the rumor that Wayne was a part of the treasure hunt. There is no other substantiation to claims of Wayne's involvement. October 1970, the digging begun using Statesman's equipment and continued for quite some time. The team quickly achieved 45ft depth, but due to large boulders were unable to dig past 85ft.
  • At Blankenship's insistence, Parker Kennedy was called in to finish. They were successful in drilling to 235ft with a 27" diameter. This drilling program did bring up thin metal and links of steel chain in addition to remnants of Spruce. The Carbon dating of the Spruce revealed that the wood was from the year 3005 AD (over 1000 years in the future), which forced the team to do additional research on the artifact, eventually determining that the spruce was covered in Pitchblende, a preserving agent used on British wood ships that has a radioactive Uranium ore component that makes the Carbon dating inaccurate. 
  • As the shaft was drilled, a 1/4" steel casing that was installed in the shaft, but only to a depth of 180ft. 

Exploration of 27in Shaft[edit]

10x cavern.jpg

After completing the shaft to the bottom of the chamber, in August 1971 Triton used a remote-controlled camera to video the bottom of the shaft. Still-photos obtained from this video is where the belief of suspicious objects at the bottom of 10X originated such as:

  • Pirate Chest with square sides and curved top
  • Pickaxe laying on the floor
  • (Severed) Human Hand 
  • Body lying on its side

In order to put eyes on the objects seen by the camera, a team of divers led by Phil Irwin of Brooklyn Nova Scotia made the first of a handful of dives in 10x.

  • On the first dive, Irwin was able to reach 180ft before reporting that there was such a strong current in the shaft that it was forcing his dive helmet off his head. This is the first event that led the Dunfield team to block off the water source from Smith's Cove. 
  • The second dive (after building a dirt caisson at Smith's cove) proved to be much calmer. Divers were able to reach the bottom at 235ft in a 7ft high cavity. 

When diver's were unable to locate any of the objects Dan believed were seen in the videos, he decided he needed to see for himself, and donned his dive gear. He also made it to the chamber at 235ft, and experienced the strong water currents, but due to poor visibility also could not see anything. Dan did a second dive in 1972, and after finding nothing of significance on that dive didn't find it worthwhile to risk a third dive. 


Since 1972, much more sophisticated camera equipment, sonar equipment and a highly qualified diver have reached the chamber at the bottom of 10x and have been unable to find any of these items, but Dan Blankenship swore to his death that they once existed. 

Blankenship Trapped[edit]



On November 26th, 1976, Dan Blankenship was lowered down into Borehole 10X to try and discover more about the mysterious treasure and the significance of the area known as 10x, when his curiosity nearly cost him his life. At a depth of 95 feet, the casing of the shaft began to collapse and Dan was almost crushed. Oak Island Treasure Co.UK hosts a transcription of their radio conversation. The picture to the left shows the collapsed section of the casing that would have entombed Dan in the 10x shaft. Following this mishap, it was clear to Dan that in order to do more exploration in 10x they would have to reinforce it with much bigger and stronger casings.

8ft Casing[edit]

10x Timeline.png

in 1978, Dan aquired three old railway tanker cars, (34ft long x 8ft round) and used these to form a much stronger casing for 10x enabling excavation of the shaft to a depth of 160ft with 8ft diameter. In order to get the tanker cars in the hole, he had to excavate 10x largely by hand to 160ft, sliding the cars in as the excavation reached new depths. Dan Henskee did a considerable amount of the work in the pit with Dan by his side much of the time. The railcars were able to reach of a depth of 126ft before Triton ceased operations leaving 10x over 100ft from the chamber. Dan appealed the directors of Triton to restore funding to the 10x project but was not successful. This difference in opinions is believed to have started the feud between Blankenship and Tobias that would eventually drive Tobias away from Oak Island and allow the Lagina team in.  

Lagina Team Exploration[edit]

One of the first areas the Lagina team explored was Borehole 10x. Although the show doesn't provide specific details about it, I believe that the Laginas felt they owed it to Dan to thoroughly explore 10X as the new partners coming in to the team. Even though The Laginas purchased their rights to the partnership from David Tobias and could have chosen any path for further exploration it is very clear that relationships, shared knowledge and courtesy is a top priority for the Laginas. At one point even when it seemed clear that there was nothing to find in 10X, because Dan was so adamant that there was something in there (lying out all his evidence on the table)- they did go back one more time.

Sonar Survey[edit]

Brian Abbot helped create a detailed sonar mapping of the chamber in the bottom which did identify some anomalies for future exploration

ROV and High resultion Cameras[edit]

  • Spectrum 90 High resolution camera was placed in 10x during the very first episode of Curse of Oak Island. The camera was unable to find anything of significance due to the extremely poor visibility caused by the excessive amounts of silt and yellow dye used to help locate the flood tunnels.
  • Season 3, Episode 1 another high resolution camera was used to identify the debris remaining in 10X that has to be removed before they can safely put a diver in the cavern. The camera also appears to have found the column Dan believes to be in the chamber, but the picture is inconclusive.
  • Season 3, Episode 5- Jake McNaughton and Larae Davis of Dartmouth Nova Scotia send a tiny ROV into the borehole with the intent of searching chamber at the bottom. The ROV is able to find the drill bar and makes it all the way into the chamber at the bottom. The pictures do appear to show one or two wood columns, but the motors on the ROV kick up so much silt that it is unable to see much else inside the chamber. 


Although there had been at least 4 dives conducted in the 1970s, there have been a few additional attempts to put eyes in the bottom of 10X recently. Prior to getting anyone safely to the bottom the team had to first remove all the debris that could cause a diver to get trapped in the bottom. This was done using an airlift system and putting people in a basket to remove obstructions. The final obstruction which could not be removed is a part of a drill bar that was dropped in years ago, and is wedged in the 27" shaft. This drill bar made an already narrow shaft even more difficult for divers to pass.

  • Dan (Frog) & Kathy (Flash) Misiaszek with John Tapper as Safety Diver (CoOI Season 2, Ep 10)
    • First dive aborted when Diver became entangled
    • Second dive canceled prior to starting due to perceived unnecessary risk and unattainable results
  • Jonathan Noiles and Dave Cousins of RMI marine
    • Cleared debris from the bottom of the 8ft chamber of 10x
    • Attaches clamps to the casing in the 27in shaft in attempt to remove casing which is unsuccessful
  • John Stabenow (Season 3, episode 5) was on scene to make the dive, but based on what was seen by the ROV didn't believe there was any value of putting a human in the chamber and declines to make the dive. 
  • Harvey Morash
  • John Chatterton with full dive support team (2017) -
    • First diver since Blankenship in the 1970s to successfully reach the bottom of 10X and explore.
    • Thoroughly investigated everything he was requested to look at, and found nothing of significance.
    • Chest-like object is believed to be a large rock that he moved- sonar scan later confirmed it was moved
    • Human figure is believed to be just a depression in the ground
    • No sign of bones or severed hand
    • Pickaxe not located, believed to be just a formation in the stones

Notes on Deep Diving[edit]

Although it was mentioned briefly in Season 3, Episode 4 of Curse of oak Island, There has not been much discussion about Martini's law with respect to deep diving. I think it is very relevant to talk about how Martini's law causes Nitrogen Narcosis with respect to divers in 10X. I don't have specific details about the equipment and/or decompression profile used by the Irwin company or Dan Blankenship- but it is my belief that neither of them were specifically trained in the use of technical gases for deep dives. If this is the case, then both Irwin and Blankenship were limited to a very minimal bottom time (Dive tables only allow 8 minutes at the depth of 130ft) without required decompression. Although we talk about the depth of the cavern being 235ft, the entire shaft leading to the cavern doesn't have to be entirely flooded. I would be willing to bet that the early dives in the 1970 were accomplished with water as low as possible making the actual water depth pretty close to the 130ft range.

In addition to the bottom-time limits imposed to prevent decompression sickness, divers using normal air (78% nitrogen/21% Oxygen) would be very likely to experience Nitrogen Narcosis at any depth exceeding 90ft (The depth limit for recreational divers is 130ft for this reason). So, while the Irwin divers may have been accustomed to diving at greater depths and may have trained themselves to be less susceptible to narcosis I highly doubt Dan Blankenship had the same level of experience. In modern technical diving the use of mixed gases (helium, nitrogen, and oxygen) can effectively illiminate the potential for narcosis, but I don't believe this would have been readily available in the 1970s- so it is very likely that Dan was experiencing Nitrogen Narcosis which could very easily explain the things he truly believed he was seeing.

Ice Holes[edit]

The exploration in 10x is credited for helping discover what many still believe is the source of water to the money pit from the South Shore. 


During a particularly harsh winter in 1979, Dan had a pump running in 10x to maintain the water level low in preparation for the next season of digging, when he noticed 4 areas just off the shore where the water was not frozen, when the rest of the cove was. He believed it was due to the warmer water coming up from the seabed from 10x that was preventing those areas from freezing. At a later date, the pump broke down, and those areas quickly froze over- indicating that there was a direct relationship between the South Shore and 10x, and possibly the entire money pit flood system. This theory was tested with colored dye a number of times in the years to come and essentially proved that there is some form of free communication between 10x, the money pit, Smith's cove and the South Shore. The same ice holes have been re-created multiple times over the years. There have been some underwater explorations of the South Shore, but nothing conclusive has been discovered to date. 

Photo Archive[edit]

Divers in 10x[edit]

  • Phil Irwin of Brooklyn Nova Scotia
  • Dan Blankenship (1971, 1972)
  • Dan (Frog) & Kathy (Flash) Misiaszek with John Tapper as Safety Diver (CoOI Season 2, Ep 10)
    • First dive aborted when Diver became entangled
    • Second dive canceled prior to starting due to perceived unnecessary risk and unattainable results
  • Harvey Morash
  • John Chatterton (2017)


Throughout this site, it is my desire to stay entirely neutral on opinions instead presenting facts that you (the reader) can interpret and come to your own conclusion, yet I try to balance this with my desire to consolidate all the known information (and opinions) in one location for each research. John Wonnacott of Blockhouse Investigations has an entire page devoted to his theory of what is or isn't located in Borehole 10X. I have included what I consider to be pertinent information here, and you can visit OakIsland Compendium if you want to read the entire article.