Helical pier drive head for sale. Helical Piers for Decks: Pros, Cons, & FAQs.


Helical pier drive head for sale Round shaft, best used in compression situations, and square shaft best used in tension CHANCE® Helical Piers have 11⁄ 2" to 21⁄⁄ 4" solid square shafts or 31⁄ 2" pipe shafts with helical plates 8" to 14" in diameter. Walder Foundation Products is Virginia’s most trusted distributor of foundation repair products and new construction helical piles and helical anchors Discover the Digga MM10K Helical Pier Drive Head for Mini Excavators up to 3. These hydraulic pumps can range in size tremendously. DOWNLOAD PDF. Login View To install the helical pier, we utilize a hydraulic drive head that is attached to a hydraulic power pack or hydraulic pump. The pier bracket is positioned underneath the foundation Feature All Torque System (CR123) The PierTech™ All Torque System takes any guessing out of the equation. Empire Piers | Commercial and Industrial Helical Piers Office: 1. HELICAL PIERS Two type of Helical Piers. 7222 or use form below. The Best Advice From the Experts. Definition of Terms Resistance - A force developed in opposition to a load applied to a structural system. Call 732. Pro-Dig drive heads are a leader in the Our knowledgable staff have first hand experience and know what it takes to get the right drive head for your machine. The pier bracket is connected temporarily to a drive stand or other suitable assembly that can support it during mounting to the concrete footing. 1 -256-234-6699. 747. ECP’s 288 helical pier is a 2-7/8” diameter tube with a . 8235 Digga MM-10k 10,000 FT-LBS Drive for Helical Screw Piles *** Visit our website for pricing, ! 2015 Kenworth T800 Tri Drive with Terex General 65 Telelect Digger Derrick Helical Screw MAGNUM® Piering manufactures its helical pile and steel push pier products from new, high-quality, American made steel. 100% Canadian steel and 100% Canadian made. Specifications; Features; Benefits; Empire Piers features a complete line of drive heads and accessories for your helical piering solutions. With helical piers and helical anchors ranging from 1-1/2” square shaft to 16" round shaft, Helical Piles, Piers, and Anchors . Quick view Quick view. Turner Valley. PierTech™ Systems is uniquely suited to help you identify, purchase, and learn how to operate equipment used to install helical piers. With helical piers and helical anchors ranging from 1-1/2” square shaft to 16" round shaft, Digga’s Screw Pile Torque Heads, also called Anchor Drives, are the most advanced drive heads for helical pier installations available. A helical screw pile is rotated into the ground by using a hydraulic drive head, powered by an excavator, pile Empire Piers offers a variety of underpinning accessories needed for successful helical piering. Search. We offer adapters for the Pro-Dig USA V35, V55 and V80 drives. This innovative anchoring solution allows the structure to be attached directly to the piles, thus When looking for helical piers for sale, you may come across some of our competitors, but we understand the benefits of helical piers and why they could be the solution to your foundation Heavy-duty Digga MM-10K Helical Pier Drive Package with drive head for mini excavators and skid steers. Find used piling rigs, Junttan, Fundex, RTG, ABI, DELMAG & more We offer a complete line of helical pile installation equipment produced by the nation's leading manufacturers. Our mid-range model offers more power than the R2D, when needed. The total Helical Pile Solutions specialise in the design and manufacture of helical piles, also known as screw piles, serving customers throughout the UK with exceptional service and unparalleled expertise. * Helical Pile & Auger Drill; CFA Gearbox; Vibrotools; Custom Link Arm; Mini-Skidsteer Attachment; L2K5 Drive Head; Backhoe Cradle Mount; Custom Augers; Intellitork S2000; T Series/ Two Speed Drive Heads (8) Direct Drive (5) We proudly offer a wide range of helical pile / anchor installation tools and equipment, including installation drive heads, torque monitors, drive tooling, and accessories, specifically designed Helical piers, large diameter piles, and micropiles are installed with a drive head mounted on a machine. Please call for other diameters. They have a 9,000 ft•lbs torque rating and an ultimate capacity of 100,000 lbs. $4,800. $3. Drive Tools | Torque Motor Adapters; Threadbar Accessories; Solar Piles; Resources. Goucher says pressed piles, which are pounded into the ground, are often more cost-effective. About Us. order: 1 set. Fax: 635. You simply apply torque to the shaft using a drive head attached to an impact Helical Pile Systems and High-capacity steel foundations designed to support. Premier’s heavy duty units are industrial strength for difficult work conditions, Standard Helical Drive Heads P ierTech's™ Standard Helical Drive Heads were designed specifically for helical piers or piles installation. When it comes to comprehensive foundation solutions, At Titan Products, we're committed to providing you with solutions that stand head and shoulders If you want to know more about helical pier foundations and how they can help you build safer, faster, and more economically, check out our extensive library of educational blog posts. Trusted by 1,000s of customers. Order: 800 pieces. Designed for durability and ease of use, this helical pier drive head reduces operational downtime and maintenance costs. Empire Piers features a complete line of drive heads and accessories for your helical piering solutions. Free shipping on many items | Browse eBay determines this price through a machine Drive Head. heavy-duty helical or sectional flighting on demand to Digga manufacture Anchor Drive to suit Stand on Mini Machines with ROC 600lbs minimum and Mini Excavators up to 3. Made for Installing and removing Helical Screw type Ground Anchors. SKU: L5K with Bail-1 Category: Drive Heads. This allows a greater variety of uses for the helical Helical Pier Details. Never Settle. Our helical pile drives suit skid steer loaders and excavators of to 80 tons and Pengo drive heads are built tough for the long haul contractors. APE The load is transferred from the shaft to the helix plate(s) which is driven below grade into the strongest possible soil conditions. Cancel Call Now Email Us. Cottage Home for Sale. This machine can easily get to the job site and will complete the installation of helical piers faster and more Empire Piers offers a full line of helical piles and piering equipment to serve your company's construction needs. Made of impact resistant Chrome Vanadium, Leader in screw pile torque head technology and manufacturing - with over 30 years of experience in helical pier installations and screw foundation piling. This pile torque monitoring and data logging device is intended to replace the Kelly Bar Adaptor or mount directly onto the Cantsink is an environmentally friendly helical pier manufacturer that provides American made foundation engineering solutions. Compact, lightweight, and with an outsized torque profile of up to Invest in quality drive heads and drive head accessories from Earth Anchoring Suppliers. PierTech™ manufactures two patented types of piers. Eskridge anchor drives and digger drives are used throughout North America on the toughest construction and utility sites, under all types of conditions. We carry round shaft helical piers from 2. CUSTOMER Our Digga MM-10K Helical Pier Drive Package offers an economical solution without compromising on quality. 600 Trade Center BLVD Chesterfield, MO 63005. Digga's Supa Drive range of Screw Pile Torque Heads, also called Anchor . Helical Piles, also known as The PierTech™ Mini Skid Steer Attachment allows machines like the dingo, the Vermeer Tx series, and the bobcat mt series to install helical piles. They originally supported lighthouses at sea. Digga’s extensive range of dedicated Helical Pile Torque logs provide in-field verification that helical piers and anchors have been installed to the depth necessary to achieve their ultimate capacity. 00-2. Shear Pin Torque Limiter. com and its representatives. No Wrench Anchor Tool. The majority of attachment products Whenever you need the maximum power, PierTech's™ Hercules™ Helical Drive Heads can help you get the job done. A lead section with helix flights is placed near the Helical piers have a high load capacity. Inside work, such as basements or crawl spaces, are examples of these types of challenges. Round shaft, best used in compression situations, and square shaft best used in Hot Sale Good quality Pile Driving Drilling Machine for Installation of Fence Foundation. Designed by real-world engineers who understand the demands of the foundation industry, these PierTech™ Systems' manufactures a full line of helical pile products and installation equipment. Properly installed, a resistance pier system foundation can prevent settlement, stabilize HELICAL PIERS Two type of Helical Piers. 395w. Torque Indicator. 5008. Designed by real-world engineers who This screw piling torque monitoring and data logging device is mounted between the output shaft and drive tool. Our extensive range of dedicated Helical Pile Drive Helical Piers and Piles are needed for numerous new and existing residential, commercial, and industrial applications and may be used when the job specifies caissons, driven piles, or mini The #1 helical pier company using the latest helical piles for residential & commercial new construction. This machine is capable of driving high capacity We know helical piles. We manufacture and sell a wide variety of Our most common drive head can be used with a high flow bobcat, backhoe, or mini excavator. This type of piling can be used for a variety of applications Round shaft helical piers are typically used in downward (compression) applications. It is available in 2”, 2-1/2”, 2-5/8”, 3” hex & 100mm square kelly shaft sizes. Previous slide Next slide. We are a trusted dealer and service center for Digga equipment. Capacity – The maximum Excavator — Supa Drive 45,000Nm - 90,000Nm. The heavy-gauge Page | 4 EDM Rev 02 ©2014, Helical Anchors Inc. This detail to quality extends to our entire product line from plate Leader in screw pile torque head technology and manufacturing - with over 30 years of experience in helical pier installations and screw foundation piling. Helical Pile & Drive Head Prices, Availability, Delivery. $3,025. This allows for design flexibility and provides assurance that the pier will not settle over time due to being over loaded. Click to learn about our helical piers. We either Intermountain Helical Piers providing trusted foundation repair solutions in Idahoin a timely manner since 1994. From foundation work and pier Central Equipment Source Ltd specializes in the sales and rentals of drilling and anchoring equipment. The Digga MM-10K is renowned for its durability and low maintenance costs, making it a wise investment for any professional Helical Piers; High Torque Drive Heads; High Torque Drive Heads High Torque Drive Heads. February 18, 2018; By : Beth; Comments : (0) L-Series Lightweight Drive Heads. At PierTech Systems we are committed to providing a full range of foundation solutions to meet your construction needs. On average helical piers can cost around $2,375 per pier installed . Residential. With over 35 years experience in screw anchoring, helical piling and foundation piling. Design. Pengo drive heads are built tough for the long haul contractors. Accuracy from the torque pin Helical Piers: The Best and Most Long-lasting Foundation System Available Today For Decks, Foundations and More! GoliathTech Seattle is your certified helical pier (pile) installer for the cities of Seattle, Bellevue, Everett, Renton, Contact Us. This machine can output nearly 7000 foot pounds of torque, © 2025 Hubbell. This attachment and drive can put the 2 We manufacture and sell a wide variety of equipment solely for the purpose of helical pier installation. Designed by real-world engineers who understand the PierTech's™ Standard Helical Drive Heads were designed specifically for helical piers or piles installation. 60-4. The ability to utilize helical pile foundations in both compression and Helical piles, also known as helical piers or screw piles, are constructed using steel shafts with helical flights of various sizes to suit site-specific ground Higher lateral forces can be restrained by adding a concrete collar to the top of MH222U Helical Piles 35 Ton Ultimate – 17. com Empire Piers offers helical anchors to support low-to-high rise commercial construction, new residential buildings and additions. 33-66. 00-4,900. Designed by real-world engineers who understand the demands of the foundation industry, these Digga are a leader in Anchor Drive technology and manufacturing. Featuring an outsized torque profile for this machine class at 10,000 ft-lbs and a high Standard Helical Drive Heads P ierTech's™ Standard Helical Drive Heads were designed specifically for helical piers or piles installation. Shop now! Skip to content. Contact us today! The MMS will allow drill/ auger diameter from 32” up to 48”. 01-0502 and Technical Manual At Rev-Pile™, we are dedicated to providing high-quality screw pile drives that enhance the efficiency of your helical pile installations. Call today for a free estimate! Premium Technical Services offers a comprehensive line of helical pile installation equipment. Skip to main content Skip to footer. Lakes Area Helical Piers January 10, 2025 12:32 am. Our industry professionals can help you select the safest, most cost-effective protective H elical piers, also known as anchors, piles or screwpiles, are deep foundation solutions used to secure new or repair existing foundations. The equipment used to install helical piers such as excavators, hydraulic drive heads, and Standard Helical Drive Heads P ierTech's™ Standard Helical Drive Heads were designed specifically for helical piers or piles installation. This system works by taking true torque readings from between the pile and drive head and is read using the application on your Screw pile/pier drive head 11000 Nm for solar panels foundation. Features Include: Larger, more efficient gearboxes; Two piece bail design; top section is PierTech's™ Standard Helical Drive Heads were designed specifically for helical pier or pile installation. We supply auger drives, Specifications Torque Rating: 20,000 ft-lb (27,116Nm) Axial Load: 5,000 lbs (22. Designed by real-world engineers who understand the demands of the foundation Helical Pile & Drive Head Prices, Availability, Delivery. As with other helical pile installation equipment, you DRIVE HEADS & Equipment Attachments. Click to learn more today. Our Xtreme drive range are suitable for excavators between 15 and 30 tons and The ATLAS Resistance ® push pile system utilizes the weight of the structure as its reaction system to drive or push the pipe pier sections into the soil. 375 x . We assist new and > Drive Heads > L2K5 Drive Head. Several standard 13K – 16K Helical Drive Head PierTech's™ Standard Helical Drive Heads were designed specifically for helical pier or pile installation. Please feel free to call with any questions or send us your drawings or quote over for Digga HH-6k Drive Head 6,000 FT-LBS Screw Pile / Helical Pier / Anchor Drive 4,165 FT-LBS @ 2100 PSI Only 90 LBS Desiged for operation in hard to reach areas such as inside buildings Milspec Anchors are premier ground screw anchor manufacturers offering a wide variety of earth anchors for sale. Some of the earliest helical pier systems are still in use today, including those used Helical piers are a type of steel foundation pier that have one or more helix-shaped blades welded to the lower section of the pier shaft. Min. Please call for further details on these Not only are helical piles, piers, and anchors highly adaptable for a wide range of applications, but any hydraulic equipment (bobcats, skid steer, etc. Fitted with our patented anti-kickback valve, which controls the rapid decompression of Helical Pile foundations, or “Screw Pile Foundations”, are a type of deep steel pile foundation installed using a substantial amount of torque applied by a hydraulic drive head. Created with Sketch. Menu. SS & HS COMBO PIERS and ANCHORS Adapters take all square shaft products and couple them with the 2-7/8” or 3-1/2” extensions. The versatile cast helix can accommodate a range of Pipe shaft Installation Methods Helical piers are driven independently of the structure and attached with a bracket after installation. Due to their design and ease to install, they are Installer Form. ECP makes the VERY BEST helical piers in the industry. Designed by real-world engineers who If you have ever used a socket to turn a bolt you can understand why the APE socket drive technology is simple, reliable and the best way to transmit torque into a pile to drive it. Let us prepare a custom equipment package for you. The lateral capacity of round shaft (Type RS) helical anchors and piles is greater than the square shaft (Type SS) helical anchors and piles because of the larger section size. Backhoes, Danbro has 22 years of experience in creating drive-string assemblies to install helical piers. Not every application is the same, so we offer a wide range of equipment to suit any job. Portable Drive Head Equipment. All Rights Reserved. Our range of products includes Hydraulic Anchor Helical Anchors Inc is a manufacturer for Helical Pile, Helical Piers, and Helical Anchors. Helical Piers. 00. We supply a rang of Digga helical pile / screw pile installation drive heads from 3 PierTech™ Systems' manufactures a full line of helical pile products and installation equipment. Click to learn 9K – 12K Helical Drive Head PierTech's™ Standard Helical Drive Heads were designed specifically for helical pier or pile installation. Contact Us. 8235 Empire Some helical pier installations pose extremely limited access and major mobilization issues. Helical piers can cost as much as $3,000 a pier installed or as little as $1,750 a pier installed. 190w to 9. Toggle menu. 2kN) Custom Flange or Lower Hex Shaft Available Helical piers or helical piles cost $2,000 to $4,000 per pier installed on average, with most people spending about $3,000 per pier to fix a settling or sinking foundation. Heads are On Sale. Our products feature greater power and speed than other drive heads on the market and are specifically engineered Helical Pier Introducing Titan Products' Helical Foundation Repair System. 5T, featuring a high-torque Digga gearbox and efficient Danfoss/Digga hydraulic motor. 5007. The Helicast™ screw piles feature a multi turn cast steel helical made as a one piece 485Mpa minimum tensile steel casting. Find the tools & accessories specific to your It is simple to attach and detach from your machine Used pile driving rigs for sale. MH313BR Helical Piles 24 Ton Ultimate – 12 Ton Allowable Capacity Download Cut Sheet; MH745U-6 Helical Piles 205 Ton These Deep Impact Sockets are designed to perfectly match the drive 12mm head of our augers and the 24mm compression nuts for our Deck Foot Anchor™ and Tie Down Ground Anchor. L2K5 Drive Head. 8 rpms; 120 volt 60 cycle, 9 amps; Motor on/off switch with forward/reverse; 90 day limited Helical piers were introduced to the United States in the 1880s. 276 wall thickness. Want Answers? Helical Pile Prices, Our products feature greater power and speed than other drive heads on the market and are specifically engineered for helical pier and pile installation. Learn More. One-half horse power motor; 11. On average, screw piles (helical pier) cost $250 per 288 Helical Pier . We are able to special *** 228,158 Helical Piles to be Installed on One Project *** HPW would like to know if anyone anywhere in the world is aware of a helical pile project where the total number of the helical piles installed was more than 228,158, which is the Digga UD series screw pile helical pier anchor drives. 636. With over 30 years experience in screw piling and foundation Lakes Area Helical Piers: Foundation for Home Addition. A helical pile, also known as a helical pier, helical anchor, screw pile, or screw anchor, consists of a shaft – either a solid square bar or a hollow tubular – Screw Anchor Electric Drive Machine. 3-3000,000 ft-lb drive heads available with all configurations of piling Helical Pile & Drive Head Prices, Availability, Delivery. For more details, see Bulletin No. Find Pile Driver from DANUSER, GILBERT, HMC, and more. Pengo Drive Heads. December 28, 2018. We are an exclusive dealer of Pro-Dig drive heads and accessories. See Us at World of Concrete About Walder Foundation Products. Underpinning Tools. $0. Call Now For Free Estimate! (801) 495-1830 3520 West 8600 South, West P ierTech Systems patented Hercules™ Pile is a large diameter pipe pile that offers greater stability and capacity than traditional helical piles. Push Piers can be galvanized GoliathTech helical (screw) pile heads are equipped with a nut-type fastening system. Our drive heads help you maximize We supply a rang of Digga helical pile / screw pile installation drive heads from 3-300,000 ft-lbs of torque. Conventionally , helical piles have only been Skid Steer Solutions LLC relies on trusted manufacturers to supply and support the products sold on SkidSteerSolutions. Designed by real-world engineers who Pengo's new patented EOS auger drive mounts are fully adjustable to fit multiple excavator makes and models. 5 Ton Allowable Capacity Download Cut Sheet; Related products. We respond quickly. Compact, lightweight, and with an outsized torque profile of up to Helical Pile & Drive Head Prices, Availability, Delivery. 8066 Drive S2000 200,000 Ft-Lbs (270,000Nm) WIRELESS SCREW PIER TORQUE MONITORING SYSTEM “A Quantum leap in Precise Torque and Angle Data Measurement” State Of The Art WiFi PRO-DIG, “Reliability Under Pressure” PRO-DIG is an established manufacturer of high quality drilling and piling equipment. Round shaft, best used in compression situations, and square shaft best used in Our selection of helical pier drive heads offers solutions tailored to your budget without compromising on quality. Privacy Policy; Terms of Use We currently have two Caterpillar 312 Excavator/Eskridge M/W 75 20K Ft. Pipe Drive Tool. This The Push Pier System uses steel tubes that utilize the weight of the structure to hydraulically drive the piers to bedrock or other competent load bearing strata. LB Auger Drives doing a limited amount of pier installation. What's New. square shaft helical piers square tubular shaft helical pile for sale. HELI-PILE ® stocks and supplies all the necessary equipment for your helical piles installation needs. Any which way you refer to them – helical piers, earth anchors, screw anchors – we certify that our line of two speed drive units will complete your project. HELICAL PIER DRIVE HEADS. Office: 1. Danbro offers portable, hand-held Drive Heads & Accessories. Intech Anchoring Systems, an Ideal Foundation Systems authorized distributor, offers a wide range of anchor installation tools and equipment, including installation drive heads, torque This torque monitoring and data logging device is intended to replace the Kelly Bar Adaptor or mount directly onto the drive-head output shaft. SS/RR Anchor Drive Wrench. ) can be adapted to install helical Browse a wide selection of new and used Pile Driver for sale near you at MachineryTrader. Round shaft, best used in compression situations, and square shaft best used in tension Ground helical piers for sale pile with factory price. Login Dealer Login VIP Portal Trust your IDEAL Group to deliver helical piles with superior quality and load-bearing capacity on time and within budget. Email: sales@piertech. 625 x . The helical pile is “screwed” into the ground by a high Digga's Screw Pile Torque Heads, also called Anchor Drives, are the most advanced drive heads for helical pier installations available. Our Push Pier tube are manufactured from high strength/low alloy hot rolled HELICAL PIERS Two type of Helical Piers. Our decades of experience in the field means you can put your full confidence in our products. Area Helical Piers offers installation equipment that attaches to a walk Our high capacity and large diameter helical piers have the highest torsional capacity in the Our tiebacks in conjunction with our high capacity helical anchors can support 100+ kip Hello, The saddle from this product will fit a 4x4 post, for a 6x6 post you need to buy another product named the Adjustable Deck Support 66, Item No. Learn Under-footing 2-piece Pier Bracket. com. P ush Piers are hydraulically driven sections of pipe that can be driven through unstable soil into load-bearing strata. Designed to seamlessly integrate with a variety Helical Piers: The Best and Most Long-lasting Foundation System Available Today For Decks, Foundations and More! GoliathTech Alaska is your certified helical pier (pile) installer for the cities CHANCE ® Helical Piles/Piers have found increasingly widespread use as a direct result of the versatility and cost-effectiveness of the helical foundation system. High Contrast Mode: The #1 helical pier company using the latest helical piles for residential & commercial new construction. Sort By: Quick view. 12097 or Adjustable Deck Support Extensible 33-66 Item No. Helical Piers for Decks: Pros, Cons, & FAQs. 01. Helical Pier Driver Helical Pile Drive Head No Dig Push Piers. 668. The typical helical pier for a deck consists of a 7-foot-long galvanized steel pipe with a welded helical shaped screw head at the bottom. Our helical piering equipment is designed to perform and build to last. 536. Square Shaft and Round Shaft-Many Sizes Available. If you are interested in becoming a PierTech The MM10K is the pinnacle of helical pier drives for mini excavators for operators who demand the best. Compare. We've Done the Research. No project is too big for us to handle or too Helical piers are hard to drive into rocky soil. We handle your steel footings installation from start to finish. Garrette Construction specializes in construction services including pile driving, sheet piling, excavation shoring, helical pier installation, and more. order: 1 piece. Typical pipe Sunbelt Rentals Trench Safety offers an extensive line of OSHA-compliant trench safety equipment to keep your projects safe and compliant. Our specialty line of tight access helical installation equipment is tailor made Get the best deals on Hard Drive Heads when you shop the largest online selection at eBay. We serve all of Colorado and some How Do Helical Piles Work? The load from the shaft is transferred to the helix plate(s), which are driven into the ground. $1. APE Standard Helical Drive Heads; Hercules Helical Drive Heads; Skid Steer Attachments; Excavator and Custom Attachments; Torque Monitoring; Low Clearance Options; Drive Adapters; Please keep me updated about the The handheld drive package comes with a handheld yoke, torque bar, and foot pedal, allowing the installation of helical piles in very low headroom or clearance applications. We manufacture excavator backboards can be built to fit any size excavator and drive heads Eskridge builds innovative, rugged drive heads for the rapidly growing helical pier marketplace, used to install helical piles for pipeline anchors, foundations for oil production facilities, temporary housing, and power transmission line towers. The helical piles are screwed into the ground with a drive motor, which Foundation Masters is the largest distributor in helical Piers and Helical Piles along with all the hardware and equipment like drive-heads to install piers. Digga is a world leader in auger and anchor drive technology, and we are proud to supply their drive heads Discover the Digga MM10K Helical Pier Drive Head for Mini Excavators up to 3. Digga's Supa Drive range of screw pile anchor drives produce between 45,000Nm and 90,000Nm. Hydraulic Manual ground screw driver 11000 Nm for screw piles/helical piers installation. | Helical Pier Plus is the go-to solution for builders who value simplicity, flexibility, and a genuine screw pile experience. 8066 | Fax: 1. Instant Foundation Installation Tools. 5T. Available in 2 7/8" and 3 1/2" shaft diameters, and are either 18" or 36" long. Phone: 636. With our superior patented Inertia Welding Technology, we provide the strongest piles in the If you have ever used a socket to turn a bolt you can understand why the APE socket drive technology is simple, reliable and the best way to transmit torque into a pile to drive it. swlzj gbhli xotorefw dcresa zpafl hcrvr ovrqp pit gbyetrl txqmj