Ottawa Journal 5 August 1887,
Article entitled "A Pleasant trip"
High Rock mine - right overhead the mountain is pierced to its summit and large buckets were continually going up and down carrying at each trip about a ton of phosphate to the opening at the summit.  These buckets are worked by machinery and the distance from the bottom of the mine to the opening at the summit is about 100 feet.  After inspecting the interior of the mine we retraced our steps to the mouth of the pit, where we boarded a car and were whisked up the steep slope of the mountain to the summit, where the works of the company are.  These cars are worked by wire cable run by machinery at the summit of the mountain.  We were surprised to learn that about 600 tons of phosphate are taken out of this mine every day, and that a gang of 150 men are continuously employed and nearly double that number could be employed were it not for the scarcity of men which Mr. Pickford informed us had considerably handicapped the company this season.  We then enjoyed a pleasant ride down the side of the mountain in a car worked by brake only.  The car flew around sharp curves down steep inclines, at a rapid rate, making the trip thoroughly exciting and enjoyable.  -- returned to Ottawa by train.
Ottawa Journal 7 July 1888.
Buckingham - The High Rock is in grand feather, the twelve new houses and other buildings erected during the winter give it now quite a village appearance.  The tramway is greatly improved by reducing gradients and straightening the track.  From 70 to 80 tons can easily be brought down to the river now.  The output at the lower level mine is very good; the week before last having beaten the record of all former times, 52 tons having been produced in one day.
Ottawa Free Press 24 April 1889
--At the High Rock and Crown Hill mines, the tramways have been at work for several days past and several thousand tone of phosphate are ready for shipment.  
Canadian Mining Manual 1890-91 The Phosphate of Lime Company owns the High Rock phosphate mines in the township of Portland West, Ottawa County, Quebec.
Ottawa Citizen 29 May 1889
All the phosphate mines are working with a full complement of men, the High Rock. The Emerald, Central Lake, Little Rapids and Canadian Phosphate Mines doing an especially satisfactory amount of work.  At the above mines an average between 170 and 200 men are employed.  The various steamers carrying the phosphate to Buckingham are busily employed, and owing to the increasing traffic, the C.P.R. has provided extra facilities for the transshipment of ore.--
Ottawa Free Press 25 July 1891
Much dissatisfaction is felt by miners, forwarders and business men generally at the order given by the government to stop all traffic on the Little Rapids on the Du Lievre after Aug. 10, until the end of the season, in order to build a dam which, it is claimed, might easily have been build last winter.  The effect of this will be that all shipments of phosphate will have to be stopped from the North Star, Ross Mountain and High Rock and Union mines unless it is done by means of a tramway and portaging.