Tamarack mine is a copper mine located in Osceola Township, Houghton County, north of Calumet, Michigan.
 The first shaft was started in 1882 and five shafts were eventually mined.
 In 1966 seven-year-old Ruth Ann Miller fell into shaft #4 and a rescue was impossible.
Pebble Mine is the common name of a mineral exploration project investigating a very large porphyry copper, gold, and molybdenum mineral deposit in the Bristol Bay region of Southwest Alaska, near Lake Iliamna and Lake Clark.
 The proposal to mine the ore deposit, using large-scale operations and infrastructure, is controversial.
 Proponents argue that the mine will create jobs, provide tax revenue to the state of Alaska, and reduce American dependence on foreign sources of raw materials.
 Opponents argue that the mine would adversely affect the entire Bristol Bay watershed; and that the possible consequences to fish populations, when mining effluents escape planned containments, are simply too great of a risk.
 Much of this debate concerns the tentative plan to impound large amounts of water, waste rock, and mine tailings behind several earthen dams at the mine site.
 The project is on hold after the loss of funding partners in 2013.
Puffing Billy is the world's oldest surviving steam locomotive, constructed in 1813–1814 by coal viewer William Hedley, enginewright Jonathan Forster and blacksmith Timothy Hackworth for Christopher Blackett, the owner of Wylam Colliery near Newcastle upon Tyne, in the United Kingdom.
 It was the first commercial adhesion steam locomotive, employed to haul coal chaldron wagons from the mine at Wylam to the docks at Lemington-on-Tyne in Northumberland.
The Stanford Tree is the Stanford Band's mascot and the unofficial mascot of Stanford University.
 Stanford's team name is "Cardinal", referring to the vivid red color (not the common songbird as at several other schools), and the university has never been able to come up with an official mascot.
 The Tree, in various versions, has been called one of America's most bizarre and controversial college mascots.
 The tree regularly appears at the top of Internet "worst mascot" lists but has also appeared on at least one list of top mascots.
Eylesbarrow mine was a tin mine on Dartmoor, Devon, England that was active during the first half of the 19th century.
 In its early years it was one of the largest and most prosperous of the Dartmoor tin mines, along with Whiteworks and the Birch Tor and Vitifer mines. Its name has several variant spellings, such as Eylesburrow, Ailsborough, Ellisborough, Hillsborough etc.
 It was also known as Wheal Ruth for a short period around 1850.
 The extensive remains lie to the north of the River Plym, less than 1 mi north-east of Drizzlecombe, on the southern shoulder of the hill called Eylesbarrow on top of which are two prominent Bronze Age barrows.
The Hedley Mascot Mine was a gold mine in Hedley, British Columbia, Canada.
 Gold was first discovered in the Nickel Plate Mountain area in 1897 and several small mines were developed over the years.
 The Hedley Mascot Mine operated between 1936 and 1949 and was one of the most unusual mining operations in the world, being built entirely on the side of a mountain, 5,000 feet above the town of Hedley or seven thousand feet above sea level.
 In the 1990s, the British Columbia government was going to burn the site down because it posed a safety risk, but the Minister of Tourism at the time intervened and, in 1995, steps were taken to preserve the site as a Provincial Heritage resource.
The Ruth Mine was a small gold producer about 65 km (40 miles) east of Yellowknife, Northwest Territories.
 It operated briefly during 1942 and then again in 1959, extracting only 550 troy ounces (17 kg) of gold thus far.
 The old mine is today (2012) significant as one of the last intact abandoned mining properties from the 1940s period in the Northwest Territories, although the site was scheduled to be remediated by the federal government.
The Robinson Mine is a porphyry copper deposit located in the Robinson Mining District, adjacent to Ruth in White Pine County, Nevada.
 In early 2012 the mine was acquired by Polish KGHM Polska Miedz.
Mascot Manor refers to a fictional house in which the Australian Football League (AFL) club mascots live.
 Prior to 2003, each AFL club had mascots; however, in order to appeal to Auskick players, a common theme was decided upon for club mascots.
 Most clubs have an historical link with their mascots.
 The story begins with Toby "Torpedo" Coleman, a young, Northern Territory boy who dreams of playing AFL, stumbling across "Mascot Manor" where the 18 mascots live.
 Some clubs have since moved away from the Mascot Manor character to a mascot of their own choosing.
Hedley is an unincorporated town in southern British Columbia, Canada, named after Robert R. Hedley, the manager of the Hall Smelter in Nelson.
 Hedley is located at the foot of Nickel Plate Mountain in the Similkameen.
 The town had a population of approximately 400 as of 2005.
 In the early 1900s, Hedley's population peaked over 1,000 people, primarily due to the gold mining industry.
 The Hedley Museum and the Mascot Mine Museum display artifacts and photographs from this era.

Question: What do Hedley Mascot Mine and Ruth Mine have in common?
Answer: gold mine