Jeffery H. Warren | Warren Forensics

Tag Archive: Jeffery H. Warren

Conveyor Backstops: Sometimes One Isn’t Enough, Part 2
October 4, 2021 4:10 pm Leave a Comment
This is the second in a two-part blog series about conveying equipment that severely injured a worker at a mine. In case you missed it, click here to read Part 1 where I describe the incident and the mining equipment. In this part, I will discuss my engineering analysis of the incident and the machinery involved and share the conclusions I reached.

The injured miner was a front-end loader operator. He was not a maintenance worker. He simply responded to a radio request for help with the conveyor. Power to the electric conveyor motors was locked out, but none of the maintenance workers did anything to lock out or block the hazardous gravitational potential energy in the heavy load of stone on the belt. (more…)
Conveyor Backstops: Sometimes One Isn’t Enough, Part 1
September 22, 2021 2:01 pm Leave a Comment
This is the first of a two-part blog series describing an incident involving conveying machinery that seriously injured a miner. Part 1 describes the machinery and the incident. In Part 2 I will summarize my engineering analysis of the incident and share the conclusions I reached.

A loaded, inclined conveyor belt may contain hazardous levels of energy due to gravity. To protect workers, anti-reverse devices called backstops are installed on inclined conveyors to prevent unexpected downhill movement. The Conveyor Equipment Manufacturer’s Association (CEMA) defines a backstop as: (more…)
Staying Connected on the Loop: Two by Two’s Mobile Internet Setup
November 19, 2020 7:52 am Leave a Comment
After completing the sit-stand workstation in the guest stateroom of our 47’ Nova Scotia pilothouse trawler, Two by Two, that I reported in a previous blog, I found I needed an internet connection with reasonable speed and reliability. While almost every marina will give you a password for their WiFi, the quality of most marina connections is unreliable and too slow to effectively work as a forensic engineering consultant. When I tried to download a simple photograph through any type of remote connection to the Irmo, SC office, I could go make a cup of coffee and come back before the download finished. To upload a group of photographs (more…)
Unguarded Shear Point on Force Tester Amputates Worker’s Finger
June 5, 2019 4:25 pm Leave a Comment
A worker was injured while testing gas springs similar to the type that hold the hatchback of an SUV open. The hazard that injured the worker was an unguarded shear point. The tester contained a mounting plate that was raised and lowered by a pneumatic cylinder.

The pneumatic cylinder lowered the mounting plate while the worker’s fingers were in the hazardous, unguarded shear point. (more…)
Case Study: Fatality Servicing Unsupported Excavator Boom
April 22, 2019 2:27 pm Leave a Comment
A mini-excavator at a job site developed a leak at a hydraulic fitting at the base of the cylinder that raises and lowers the boom. A subcontractor foreman at the site raised the boom to search for the leak. The foreman found and attempted to tighten the leaking fitting. When he did, the fitting separated from the base of the cylinder, releasing the hydraulic pressure that held the boom aloft. The boom fell and the bucket struck a nearby superintendent for the general contractor.

(more…)
Defective Vertical Baler Causes Serious Crush Injury to Operator’s Arm
January 29, 2019 5:08 pm Leave a Comment
I recently worked on an interesting case involving a box baler. An employee of a butcher shop put some empty cardboard boxes in a vertical box baler and pushed the control switch to compact the boxes. After the 30 by 60 inch platen weighing 851 pounds returned to its raised position, the employee reached into the open space above the bottom door on the baler and began to clear cardboard from the bale tie slots in the bottom of the raised platen. Suddenly, and without warning, the steel pin attaching the platen to the raised hydraulic cylinder rod failed. The heavy steel platen fell and crushed his arm which was outstretched over the baler door into the compaction space.

(more…)
Children Will Fall At Playgrounds. What Shall We Do To Protect Them? A Multipart Blog Series – Part III: An Overview of Selected Playground Safety Technologies
May 7, 2018 3:04 pm Leave a Comment
Welcome to the third and final post in our multipart series of blog posts about a young boy’s fall and serious injury at a public playground. In our first post we gave a brief overview of the incident and our investigation. In the second post we discussed some of the safety standards applicable to public playgrounds. In this post, we will examine some of the impact-absorbing playground surfaces available to protect children at playgrounds from injury. If you would like to read the first two posts, they are available here and here.
(more…)
Case Study of an Injury Involving a Soil Mixer
October 6, 2016 9:47 am Leave a Comment
In May, 2014, a plant farm worker was seriously injured when he fell into the hopper of an electrically powered soil mixer. The mixer in question used a rotating steel ribbon powered by a 7-1/2 hp electric motor to mix batches of materials such as sand, mulch, wood shavings, fertilizers and other landscaping materials to create potting soil. At the top of the hopper sidewalls, within 6 inches of the ribbon, was a steel grate. (more…)
A Case Study in a Coal Mine: What are a Machine Rebuilder’s Responsibilities?
September 6, 2016 2:24 pm Leave a Comment
In November of 2010, a miner was injured by a roof bolting machine (roof bolter) in an Alabama underground coal mine. The roof bolter in question had undergone a complete rebuild intended to return the machine to the original equipment manufacturer’s (OEM’s) specifications. Warren was hired to analyze both the design of the roof bolter and the actions of the rebuilder to determine if either contributed to the unfortunate coal miner’s serious injury. Background information on coal mining and roof bolters, as well as an analysis of the roof bolter and the actions of the rebuilder are included. (more…)
Manufacturer Settles with Operator Injured by a Flying Tool Fragment from Milling Machine
September 29, 2015 1:23 am Leave a Comment
In my June 2015 blog, I discussed a personal injury case where the jury decided that the lack of interlocks on the covers of a swamp cooler did not render it defective, even though it was technologically feasible to do so and their existence would have prevented the amputation. Conversely, in another interesting personal injury case involving a computer numerically controlled (CNC) milling machine, a large settlement was made by the manufacturer with the injured operator because the machine did not have adequate interlocks on its enclosure doors. (more…)

Type ofLoss

Not sure what you're looking for?
Browse All

Select Loss Category

Select Sub-Category (choose category first)

View Now