Lawrence Hager Trimmer (1847-1909) was a commanding presence in the Middle Valley community, representing the Second District of Hunterdon County in the New Jersey State Assembly from 1889-1891, founding and serving as director of the High Bridge National Bank, manufacturing peach baskets with 30 workers producing 4,000 daily, and operating the Middle Valley Trap Rock and Mine Company, which supplied crushed gneiss and diabase from quarries in this ravine for macadam road surfaces and railroad ballast. Mining at Teetertown began in 1896 and reflected the highly mechanized methods used widely in the northeastern U.S. during the Victorian Era, with 2-1/4' wide by 6"(+/-) deep holes drilled into the rock face by drills powered by a 150 horsepower steam engine, dynamite packed into the holes with paper and gunpowder fuses, blasted rock crushed into smaller stone and gravel, and quarried stone loaded into ore carts that were winched uphill over small-gauge rails by a 3/4" steel cable powered by a single-drum steam hoist and transferred onto the railroad. At peak production, the plant could haul 400 tons of rock daily and employed 35 laborers, mostly of Italian and Greek heritage, who slept in wooden shanties; the site also included a boiler house, blacksmith shop, coal bins, and a keg house where beer was stored and served. In 1897, the 1.3-mile Middle Valley Railroad, the shortest independent entity in the state, was built for $10,548 to carry ore to the Central Railroad of New Jersey near Middle Valley Road. Quarry drilling and blasting were dangerous because the drilling pattern, hole depth, and amount of dynamite determined both how much rock would be dislodged and where it would fall, and mistakes could be fatal. One of the worst tragedies came on November 12, 1904, when Anthony Trimmer (1883-1931), Lawrence Trimmer's personal business representative, and his brother Grover Cleveland Trimmer (1884-1904) worked on a frigid Saturday morning; after two sticks of dynamite were brought into the boiler house to keep dry, Grover invited Anthony to join him there for lunch, and as Anthony approached after retrieving his meal from the blacksmith shop, the boiler house exploded, shattering nearby windows. Quarry workers and Anthony pulled Grover from the wreckage by hand, but he was badly burned and mangled, taken by wagon to his parents' home, and died several hours later; he was buried in the Lower Valley Presbyterian Church cemetery. Lawrence Trimmer never recovered from the loss, died five years later, and was buried beside his son. Another son, Lamont (1881-1965), continued operating the company until a dwindling customer base and financial problems forced it to cease production in 1923.